Practice areas

Crime, Regulatory, Judicial Review

Year of call: 1986 (QC 2011)

William (Bill) Mousley Q.C. is predominantly a criminal practitioner, specialising in cases of homicide, fraud, road death, serious sexual assault, serious violence, money-laundering, drug importation and supply, including confiscation. He prosecutes and defends in equal measure and is one of the busiest and most successful Silks on the Western Circuit. As Leader of the Circuit, he is instructed in the most serious and high-profile cases. His reputation and popularity extends to London, the South East and the Midlands.


“…engaging, willing to listen, to reason and to rationale…”

“…excellent advocacy…”

“…he is to be complimented for his skilful advocacy, mastery of a huge quantity of material and very attractive presentation of this very complicated case…”

“…beyond our high expectations and acheived an excellent result…”

“…skilfull advocacy in prosecuting this case…”

“…we were extremely impressed with his positive approach, understanding and advocacy skills throughout…”

“…enthusiasm and skill…”

“…his usual stellar performance…”

“…excellent written and oral submissions in this difficult case…”

Read More

He regularly appears before the Court of Appeal, and his cases are often reported.

He also has a successful Judicial Review  practice in recent years, especially in cases where tribunal decisions fall into question, appearing before the Administrative Court.

He is an experienced  Recorder in Crime and Civil Law.

He is a member of the RFU Disciplinary Panel, dealing with players in the top four levels of England Rugby who have received red cards or been cited for foul play.

William regularly speaks at legal seminars to a wide variety of audiences.

He is the Head of Chambers.

Public Access

As well as working conventionally as instructed by a solicitor, he is also authorised to accept work directly from a member of the public or any organisation.

Recent Cases


  • R v T, Snaresbrook CC, July 2017 – defence of learning disabled young defendant for conspiracy to murder with two others – intermediaries involved
  • R v ZY, Central Criminal Court, May 2017 – defence of one of six defendants charged with gang-related stabbing – young defendant – joint enterprise – cut-throat defence – acquittal following a 6 week trial
  • R v M, Winchester CC, February 2017 – prosecution of a young defendant for murder of his baby child, baby shaking and multiple fractures – extensive and disputed expert evidence on causation, convicted after a 6 week trial
  • R v B, Bristol CC, October 2016 – prosecution of 3 brothers for murder and attempted murder by shooting – joint enterprise – three other defendants charged with subsidiary offences including assisting offenders – all those involved members of the travelling community, all convicted after a 5 week trial
  • R v T, Winchester CC, July 2016 – defence of a man charged with murder of his ex-lover in Dorset – domestic violence background – self-inflicted injuries, alleged amnesia for events – 3 week trial
  • R v M, Winchester CC, May 2016 – successful prosecution of murder of a sex worker, involving complex psychiatric evidence and of bad character
  • R v W, Winchester CC, May 2016 – successful prosecution of axe murder by person affected by legal highs – most savage attack ever seen by pathologist
  • R v P, Winchester CC, April 2016 – 4 week trial, successful prosecution of murder and attempted murder of drug dealers by a drug dealer – issues of self-defence, intent, loss of control – reluctant witnesses-bad character of all parties-complicated disclosure decisions
  • R v MH, Winchester CC, January 2016 – 7 week trial, defending in a double-jeopardy murder as a result of new and compelling evidence following previous acquittal – Court of Appeal hearing to quash acquittal and subsequent re-trial – ground-breaking DNA evidence – vulnerable and elderly victim
  • R v H, Winchester CC, December 2015 – successful prosecution of murder by arson by sex worker on vulnerable alcoholic in his own home – very complicated and contested psychiatric evidence from 4 experts
  • R v M, H, I & D, Bristol CC, October 2015 – 6 week trial, successful prosecution for the murder of Bristol teenager Becky Watts and her subsequent dismemberment and concealment – four defendants, including step-brother – daily national press interest and TV coverage, including subsequent documentaries – the largest ever police investigation in Bristol – also offences of assisting offenders – case was presented using digital technology – issues of bad character and joint enterprise – particular family sensitivities
  • R v M, Winchester CC, July 2015 – successful prosecution of murder of elderly woman in her own home – sexually motivated – death following from serious sexual assault – novel expert evidence on cause of death from faecal peritonitis following insertion of object
  • R v H, Winchester CC, June 2015 – successful prosecution of paranoid schizophrenic for murder of elderly man – psychiatric defence rejected despite well-established and detailed medical medical history
  • R v F, J & C, Winchester CC, May 2015 – prosecution of murder of drug addict by other addict, in course of violent burglary – issues of intent and joint enterprise
  • R v R, Luton CC, February 2015 – prosecution of 16 year-old for murder – gang-related violence – reluctant witnesses, sensitive disclosure issue


  • R v J, Leicester CC, April 2017 – defence of man for minor assault on an alcoholic leading to unexpected death – issues of causation – lawfulness of actions – defendant had life-threatening allergies and history of ill-health
  • R v C, Winchester CC, March 2017 – defence of law student for one-punch manslaughter on the Isle of Wight – self-defence – bad character evidence – 3 week trial


  • R v W & W, Lewes CC, January 2013 – Successfully prosecuted a husband and wife organised crime team who had defrauded company creditors, mortgage lenders and finance companies of several million pounds before laundering the proceeds by a number of complex transactions as well as trying to conceal their real assets when they were each declared bankrupt. Investigation carried out by South East Regional Organised Crime unit. The frauds were carried out over an eight-year period up to the end of 2010. He was complimented for his skill and hard-work, mastering more than 10,000 pages of evidence and presenting the case in a clear, attractive way.

Sexual Offences

  • R v SD & others, Oxford CC, September 2017 – prosecution of rape and child sexual exploitation allegations made against 19 defendants
  • R v P, Harrow CC, January 2017 – prosecution of ‘date-rape’ on vulnerable young person with use of drugs – re-trial following previous successful appeal
  • R v M, Southampton CC, September 2016 – defence of knife-point rape charge by defendant with similar previous convictions – complex bad character – life sentence on conviction
  • R v W, Exeter CC, September 2015 – 5 week trial, defending mother of numerous children and their friends abused over many years by her and her husband – links to Rosemary and Fred West – 12 victims and other complainants – very significant history of care and social services involvement – vulnerable witnesses – life and extended sentences imposed
  • R v H, Chichester CC, May, 2015 – successful defence of man for alleged historical abuse including rape of family member

 Reported Cases

  • R v Wells [2015] 1 Cr.App.R (S) 33
  • R v Pisano [2015] 1 Cr.App.R 27
  • R v Knight [2003] EWCA Crim 1977; [2004] 1 Cr. App. R. 9, CA
  • R v Hawar Hussein Ali [2003] EWCA Crim 3214; [2004] 1 Cr.App.R. 501


  • LLB


  • Middle Temple

Click here for my Personal Privacy Statement