Katie Mustard

Katie Mustard

Junior Counsel

CALLED

2014

"Very impressive, a cut above the rest at her level."

Chambers UK, 2025

 
 
 

On this page

Katie has a busy criminal practice prosecuting and defending in the Crown Courts and Youth Courts. She has successfully dealt with a range of cases across the criminal spectrum including sexual offences, gang-related offences and fraud.

Katie also has a regulatory practice, primarily focusing on health care and education regulation. She frequently receives briefs to appear as a case presenter for different regulators. Katie also represents individuals who are appearing before their regulator. She has particular expertise in advising and representing clients before the General Medical Council (GMC), the General Dental Council (GDC), the Nursing and Midwifery Council (NMC), the Health and Care Professions Council (HCPC) and Social Work England (SWE). Furthermore, Katie has experience of representing individuals at University Disciplinary hearings.

Katie has undertaken investigatory and public inquiry work. She successfully completed an ‘Investigative Interview’ course with Intersol Global in 2017 – this has assisted her with undertaking the early stages of investigation in respect of private prosecutions. Katie was instructed as part of a team working on the Grenfell Tower Inquiry. Her role involved taking witness statements from individuals at the Royal Borough of Kensington and Chelsea and assisting with disclosure reviews.

Katie has also appeared in cases prosecuted by charitable organisations, including the RSPCA.

She is on the CPS Extradition Panel (Grade 2). She has represented Issuing Judicial Authorities (IJA’s) at extradition hearings and at the High Court.

Katie is a qualified pupil barrister supervisor.

Background and Expertise

Prior to joining chambers, Katie worked as a legal assistant within the regulatory department at Kingsley Napley. She undertook work for regulators and individual registrants. This experience means that Katie is extremely familiar with the work that those instructing her are undertaking and how she can best assist in both the preparation and presentation of cases.

In 2018, Katie was seconded to CPS London where she litigated a full range of criminal cases. This experience gave Katie great insight into the workings of the CPS and she is now a CPS panel advocate at Grade 3. As part of the secondment Katie spent time on a specialist domestic abuse unit and now has particular expertise both prosecuting and defending this category of case.

Katie has completed the vulnerable witness training course through Lincoln’s Inn. She is regularly instructed in matters involving both vulnerable witnesses and defendants.

Notable Cases

Disciplinary and Regulatory

NMC v Dr CM, 2022-2024

Katie is currently part-heard presenting the largest case the NMC has brought to a hearing.

The case involves allegations that the Registrant assessed and diagnosed FGM in children where it was outside the scope of her role/competence to do so.

The matter started with over 1,000 charges. Katie was tasked with re-drafting and scheduling the charges to make presentation of the case more efficient. 

The panel’s written determination to date runs to almost 600 pages.

Read more on BBC News

GDC v MK, 2024

Katie represented a dentist who had been suspended by the GDC because of allegations made by his ex-wife, which were also being investigated by the police. Following a decision by the police not to charge the dentist Katie persuaded the GDC that an interim order was no longer necessary, and the dentist was allowed to return to work.

SWE v IF, 2023-2024

Katie is instructed by Social Work England in a case where the Social Worker faces several charges including failures to safeguard a child who had unexplained injuries.

On the first day of the hearing the Social Worker made disclosure requests regarding a key witness’s own fitness to practise referral. Katie was required to advise on disclosure obligations whilst formulating an appropriate response to the panel.

Later during the hearing another key witness unexpectedly withdrew their support. Katie advised on options whilst also preparing a written hearsay application which ultimately succeeded.

GMC v TY, 2024

Katie advised a Dr client suffering with serious eating disorders. The Doctor was cautioned by the police after she had stolen food items from a supermarket. Further incidents were later discovered, and she was charged with several counts of theft amounting to over £7,000.

Katie was involved in the case from an early stage advising on the regulatory and criminal implications and need for expert evidence, which was obtained.

Katie appeared for Dr. TY at early court hearings was involved in discussions with the Crown about acceptable disposals as well as advising on communication with the GMC throughout. 

GoC v BR, 2023

Katie was instructed by the GoC in a case involving allegations that the student optometrist submitted false documents to his university to qualify for mitigating circumstances and progress his studies without passing certain modules.

At a late stage during the hearing the Registrant made an application to adjourn in order to present expert evidence to the committee regarding his mental health.

After reviewing medical reports and advising on the implications of an adjournment (which would have allowed Mr. BR to conclude his studies) Katie successfully opposed the application.

The committee found the Registrant’s dishonesty to be ‘sustained and elaborate’ and he was subject to an erasure order. 

Disciplinary and Regulatory
Drugs

R v BJ and others [Operation Dextran], 2021-ongoing

Katie -led by Robert Evans (15NBS)- is instructed by the Crown in a multi-handed drugs conspiracy case involving EncroChat evidence. Following the granting of funding for a defence expert this case is now one of the primary cases in which disclosure arguments are being run.

Snaresbrook Crown Court

R v DS [Operation Sharpner], 2024

Katie – led by Corinne Bramwell of chambers – was instructed by the Crown in a drugs conspiracy case involving EncroChat evidence. DS acted as a conduit for the supply of over 5kg of cocaine. DS pleaded guilty just before the start of the trial and was sentenced to over 7 years imprisonment. 

Wood Green Crown Court

R v GN, 2020

Katie represented a client who was charged with cultivation of cannabis and abstracting electricity. Following representations the Crown did not pursue the abstracting electricity charge and the client received 8 months imprisonment for the cultivation of cannabis, which he had pleaded guilty to.

Snaresbrook Crown Court

R v HL, 2019

Katie represented a man accused of permitting his property to be used to cultivate cannabis. He was charged alongside his wife and son. Following representations from the defence the Crown offered no evidence against Katie’s client and his wife.

Woolwich Crown Court

Drugs
Extradition

Hungary v LF, 2020

Katie was instructed by the CPS on behalf of the Hungarian authorities. This case concerned a warrant for seven different offences including violation of lease terms and accounting omissions. The issues raised included dual criminality. Following submissions from the IJA to this effect the court discharged the requested person in respect of two of the offences (noting that his speciality would be protected in respect of the discharged matters by the operation of Article 27 of the Framework Decision) and ordered extradition in respect of the remaining matters.

Romania v LN, 2020

Katie was instructed by the CPS on behalf of the Romanian authorities. The requested person was tried in his absence in Romania and he asserted that he was unaware of the proceedings against him. The issue in the case therefore largely centred around the requested person’s fugitive status. Following submissions the Judge found the requested person to be a fugitive and ordered his extradition.

Extradition
Financial Crime

R v JH and others / R v SB and others, 2023

Katie, led by Rhiannon Sadler of Chambers, prosecuted two trials involving conspiracies to commit fraud against online gambling company Bet365. The two trials – which lasted around 7 weeks in total- followed a lengthy and complex investigation by Kent and Essex Serious Crime Directorate and the CPS Complex Casework Unit.

The matter was reported in the press here

Basildon Crown Court

R v PT, 2021-2022

Katie, led by Katrina Charles of Chambers, prosecuted a three-month case where the defendant was convicted of 11 counts of fraud. The defendant had offered to value antiques – usually owned by elderly or vulnerable individuals – and instead treated the items as his own, either storing or selling them.

The matter was reported in the press here

Isleworth Crown Court

R v JM, 2019

Katie prosecuted a man who was sentenced to three and a half years for committing bank frauds which totalled in excess of £100,000.

Reported in the press here

Financial Crime
Firearms

R v AK, 2023

AK was initially charged with offences at Kingston Hospital including discharging CS spray at security guards [firearms offence], causing an evacuation.

During proceedings AK was frequently sectioned and would commit further offences once well. After the third set of offences, she was remanded.

Katie advised on obtaining expert evidence and options arising from this once received. Katie was closely involved in negotiating acceptable disposals/pleas with the Crown based on AK’s vulnerabilities and poor mental health.

The Judge commented that this was the most unusual case he had seen in terms of sentence but ultimately bailed AK, deferred sentence and then passed a community order for all matters.

Kingston Crown Court 

R v BB, 2022

Katie defended an individual charged with possession of a shotgun and ammunition, which carries a mandatory minimum sentence of 5 years. In addition to the firearms offences Katie’s client had already pleaded guilty to being in possession of cannabis with intent to supply it to others. Katie’s client pleaded guilty to the firearms offences and following mitigation he was sentenced to the minimum term of 5 years, with the sentence for the drugs matter to run concurrently.

St. Albans Crown Court

R v CT, 2019

Katie represented a client who was facing firearms and drugs charges. He was charged with an offence under the Firearms Act which carries a mandatory minimum 5 year prison sentence and possession of Class B drugs with intent to supply (PWITS). Consequently, the client was facing an immediate prison sentence of several years. At court the Crown accepted pleas to a lesser offence under the Firearms Act and simple possession of the drugs. Katie was then able to persuade the Judge to impose a total sentence of 7 months imprisonment suspended for 18 months.

Isleworth Crown Court

Firearms
General Crime

R v RT, 2023

Katie defended in a case involving a number of allegations of breach of a non-molestation order. Mid-way through the trial new evidence came to light and Katie successfully argued its admissibility. The jury returned unanimous not guilty verdicts.

St. Albans Crown Court

R v JH and others, 2022

Katie prosecuted a three-handed case involving a ‘crime spree’ of offences committed in June 2019, including a night-time dwelling burglary. Pleas were entered on the morning of trial and the first defendant was sentenced to 4 years 6 months imprisonment, the second defendant was sentenced to 3 years imprisonment and the third defendant received a suspended sentence.

Aylesbury Crown Court

R v ME and others, 2021

Katie, led by Tessa Shroff of chambers, prosecuted a multi-handed conspiracy to rob case. The case involved a group of males breaking into a property in the middle of the night and demanding money from the occupants. One of the occupants of the property was beaten and another was stabbed. The first defendant pleaded guilty on day 3 of the trial and the other defendants were all convicted by the jury.

Basildon Crown Court

R v B, 2021

Katie represented a youth charged with a knife point robbery at trial. The allegation was that threats had been made with a knife in order to steal a designer coat. The complainants’ statements were admitted as hearsay. The jury returned a unanimous not guilty verdict in respect of Katie’s client.

R v KH and RO’D, 2021

Katie prosecuted two men charged with the robbery of a taxi driver. The incident was caught on dash-cam footage where the men could be seen to use a mobile ‘phone charging cable to strangle the driver. The defendants were sentenced to 10 years imprisonment and 11 years, 4 months’ imprisonment respectively.

The matter was reported in the press here

Basildon Crown Court

R v RH, 2020

Katie represented a client charged with breaching a restraining order. She submitted written representations to the Crown stating that prosecution was not in the public interest due to – in part - the delays caused by Covid-19. Katie’s representations persuaded the Crown to drop the charges against her client.

Croydon Crown Court

R v UH, 2019

Katie prosecuted a Newton Hearing in respect of a child abduction matter. The issue in dispute was whether the 13 year old complainant had been threatened during the time he had been abducted. The Judge found that threats had been made and sentenced the defendant to 28 months imprisonment.

Snaresbrook Crown Court

R v MD, 2019

Katie prosecuted a case involving prolific burglary offending. Following numerous court appearances the defendant was sentenced to over 10 years imprisonment.

Croydon Crown Court

R v DON, 2019

Katie prosecuted a man who stole nearly £10,000 from his mother whilst she was unwell and in hospital. He offered a plea on the day of trial and was sentenced to 15 months custody.

Woolwich Crown Court

R v BT

Katie represented an individual who was accused of possessing a bladed article. The charge was his second such offence and, consequently, he was facing the mandatory minimum six month sentence if convicted. Katie’s speech to the jury focused on the ambiguity of the DNA evidence and forensics. The jury returned a unanimous not guilty verdict.

Cambridge Crown Court

R v ES

Following guilty pleas to a number of offences which were committed in the course of a suspended sentence Katie successfully persuaded the court to only activate the suspended sentence in part. Katie’s submissions had the effect of reducing a likely sentence of over two years down to a sentence of 18 months.

Crown Court at Chelmsford

Crime
Healthcare

HCPC v IY, 2021

Katie represented a paramedic who was accused of mismanaging medication at a large event. After representations were made by Katie the HCPC amended the charges to reflect that this was an omission, rather than a wilful act. On this basis the charges were admitted, and Katie persuaded the panel not to find current impairment.

NMC v JB, 2021

Katie represented the NMC in a case involving allegations that nurse JB did not intervene when detention officers were choking a detainee at Brook House Immigration Removal Centre. The allegations came to light due to covert filming for BBC Panorama. The panel found current impairment and struck JB off the professional register.

NMC v KW, 2020

Katie was instructed by the NMC mid-way through a substantive hearing which ran for over 10 weeks in total. The charges related to a range of misconduct matters alleged against an independent midwife. Katie was required to review complex medical evidence and cross-examine the defence expert at length.

NMC v DK, 2019

Katie presented a three week midwifery case where the Registrant faced over 50 misconduct charges including undertaking intimate examinations when they were not clinically indicated. The panel found most of the charges proved and struck the Registrant off the register.

NMC v RB, 2019

Katie presented a case where the Registrant’s omissions related to a particularly vulnerable patient, who sadly died. Following a 7 day hearing, which involved evidential issues regarding the Coroner’s inquest, the panel found all the charges proved and cautioned the Registrant.

NMC v JD, 2019

Katie presented a case where the Registrant was accused of clinical misconduct as well as stealing a blue disabled badge permit and using this fraudulently. Following a 7 day hearing the panel found the charges proved and struck the Registrant off the register.

Healthcare
Rape and Sexual Offences

R v CF, 2024

Katie represented an operating department practitioner facing two counts of sexual assault occurring in an operating theatre – one against a patient and one against a colleague.

Significant disclosure about the colleague was received. Following receipt of this Katie drafted a s41 application which -whilst unsuccessful -led to the Judge allowing certain lines of questioning.

At the outset of trial, the patient provided a withdrawal statement. She was ultimately persuaded to give evidence, but the jury acquitted in respect of her allegation.

CF received a suspended sentence in respect of the assault against his colleague.

Portsmouth Crown Court

R v JW, 2021-2024

Katie is representing a female defendant charged with sexual assault against two teenage girls in an on-going case. One of the complainants did not wish to provide a statement and therefore careful cross examination of the other complainant was required to deal with both matters.

St. Albans Crown Court

R v GH, 2022

Katie defended in a possession of indecent images of children trial which required extensive cross examination of the prosecution expert about technical matters relating to VPN’s, torrents and accessibility of images.

Woolwich Crown Court

R v FR, 2019

Katie prosecuted an extreme pornography trial where the defendant was accused of possessing a number of videos depicting sexual conduct with animals.

Maidstone Crown Court

Rape and Sexual Offences
Safeguarding

SWE v SM, 2022

Katie provided investigative advice on a case involving allegations of historic abuse and neglect from 1993-1997 at a children’s home.

BHA v JF, 2021-2022

Katie, led by Jane Bickerstaff KC of Chambers, prosecuted the first Safeguarding case brought by the British Horseracing Authority (BHA). The trainer, JF, was found to have breached the BHA’s safeguarding rules, aimed at protecting young persons and adults at risk. JF was permanently excluded from racing for a period of seven years.

The matter was reported in the press here

SWE v RF, 2021

Katie represented a social worker who admitted that she had disclosed confidential information about children without a professional reason to do so. After hearing evidence from the social worker, her manager and submissions from Katie the panel found that the social worker’s fitness to practice was not currently impaired.

Safeguarding
Violence

R v LW and another, 2024

Katie represented the first defendant in a causing grievous bodily harm with intent (s18) trial. The allegation was that Katie’s client (LW) and his friend had been involved in an attack on LW’s neighbour following an argument just outside their premises. More than one verdict was left open to the jury and Katie’s client was the only defendant to be unanimously acquitted of all matters.

Woolwich Crown Court

R v GG and Others, 2023

Katie was instructed to represent the first defendant in a multi-handed s18 where the complainant had been attacked in a nightclub and suffered significant facial fractures.

The incident was caught on CCTV which showed GG stamping on the complainant’s head whilst he was on the ground. The defence was self-defence. GG was also charged with causing actual bodily harm (ABH) to the complainant’s friend.

At trial the complainant and his friend were cross examined in a manner which showed that their memory of the night was not accurate.

Katie’s client was unanimously acquitted of both charges he faced.

Chelmsford Crown Court 

R v B and B, 2020

Katie represented two brothers (aged 16 and 17) who were both charged with causing grievous bodily harm with intent (s18), following a stabbing.

Following representations from Katie the Crown accepted a plea to s20 from the younger brother and he was sentenced to a Youth Rehabilitation Order with intensive supervision and surveillance.

St. Albans Crown Court

R v UN

Katie successfully defended a young client accused of ABH who was jointly charged with others. At trial Katie made an application to adduce the complainant’s bad character and this was admitted into evidence. She then cross-examined the complainant about the inconsistencies in his evidence and he accepted that his evidence differed from the account which he gave to the police.

Oxford Youth Court

R v AH, 2018

Katie secured a conviction for ABH following an incident where the defendant had assaulted a local resident who had questioned why he was loitering in the bin sheds at his block of flats.

Inner London Crown Court

Violence

Achievements

Memberships
  • The Honourable Society of the Inner Temple
  • Criminal Bar Association
Appointments
  • CPS RASSO Panel
  • CPS Panel (Grade 3)
  • CPS Extradition List (Grade 2)
  • Qualified pupil barrister supervisor
Education
  • BPP (2014) - Bar Professional Training Course – Outstanding
  • Birmingham City University (2012) – LLB Law Hons – First-Class with Honours
Activities and Interests
  • Travel
  • Hiking
  • Cookery

"Katie is without doubt a natural at regulatory and disciplinary work."

Legal 500, 2025

"She is a fantastic practitioner - very charming and patient. She gets the job done."

Chambers UK, 2025

"She gives very sound advice and wins the confidence of her clients."

Legal 500, 2025

"Approachable and provides succinct advice."

Chambers UK, 2024

"Whether presenting ostensibly simple cases or cases of the utmost complexity, Katie provides clear, well-reasoned and focused advice."

Legal 500, 2024

"A rising star."

Chambers UK, 2024