Katie Mustard


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.

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

Background and experience

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

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 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.

NMC v CM, 2022 - (on-going)

Katie is currently part-heard presenting (as junior alone) what is understood to be the largest case that the NMC has brought to a hearing. The matter started with over 1,000 charges.

The hearing stated in May 2022 with an initial time estimate of 8 weeks but now has dates for 17 weeks going in to 2024.

The case involves allegations that the Registrant performed deinfibulation (FGM reversal) in circumstances where it was outside the scope of their role to do so.

GoC v BR, 2022-2023

Katie was instructed on behalf of the GOC to present this case involving allegations that the student optometrist submitted false documents to his university in order to qualify for mitigating circumstances and progress in his studies without passing certain modules. The student was subject to an erasure order.

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.

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.

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 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 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 BJ and others, 2021 (on-going)

Katie is currently being led by Robert Evans (15NBS) in a multi-handed drugs conspiracy case involving EncroChat evidence. Snaresbrook 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.

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.

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.

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.

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.

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 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 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.

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.

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.

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.

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.

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.

Read more Notable cases


"A rising star."
"Approachable and provides succinct advice."
Chambers UK, 2024
"Katie is an absolute pleasure to work with; she is very knowledgeable and pragmatic with a keen eye for detail."
"Her work was of an exceptionally high standard, beyond what you would expect for her year of call."
Chambers UK, 2023


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PROFILE: Katie Mustard

Chambers UK, 2024 Legal 500, 2024

Year called




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Regulatory / Disciplinary


020 7489 2727


BPP (2014) - Bar Professional Training Course – Outstanding

Birmingham City University (2012) – LLB Law Hons – First-Class with Honours


The Honourable Society of the Inner Temple

Criminal Bar Association


CPS Panel (Grade 3)

CPS Extradition List (Grade 2)


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