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Deanna Heer KC

Appointed Senior Treasury Counsel in 2022, Deanna is a highly experienced criminal barrister who is regularly instructed in the most serious and high-profile cases and accepts instructions on behalf of both the prosecution and the defence.

For over a decade she has specialised in cases of homicide at the Central Criminal Court. In 2020 she was named The Times Lawyer of the Week following her successful prosecution of Jonty Bravery who threw a child from the viewing platform of the Tate Modern. This year, she has been shortlisted as Crime Silk of the year by the Legal 500.

She frequently appears before the Court of Appeal in respect of appeals against conviction and sentence and advises the Attorney General on References to the Court of Appeal on questions of law and sentencing. In 2021, following a four-day appeal which involved questioning multiple experts she successfully persuaded the Court of Appeal to uphold the convictions in the case of the so-called ‘Freshwater Five’.

Deanna is also an acknowledged expert in health and safety law and has specialised in this area for many years, appearing in the leading case of R v Tangerine Confectionary and Veolia (ES) UK in the Court of Appeal.

She is experienced in appearing at inquests, including those involving juries, and was recently instructed in the inquest into the death of Belly Mujinga who died during the Covid 19 pandemic.

She sits as a Recorder of the Crown Court.

Notable cases


  • R v Mitchell: Prosecution of high-profile case of murder following the discovery of the headless body of a woman who had gone missing from her home. It was alleged that the defendant killed the victim, removed her body in a suitcase and then forged her will in order to obtain her estate. The sentencing hearing was the first, in a case of murder, to be televised.
  • R v Vig: Prosecution of man who murdered his elderly father by bludgeoning him to death with a champagne bottle. The case raised issues relating to the defendant’s mental health and whether symptoms of autism spectrum disorder meant that he did not intend the consequences of his actions.
  • R v Hilden: Prosecution of man who murdered his cell-mate at Belmarsh Prison. Deanna has repeatedly been instructed to prosecute killings in prison and has particular experience of managing the complex disclosure issues that can arise in these cases.
  • R v Bravery: High-profile prosecution of adolescent with mental health disorders who threw a child from the balcony of the Tate Modern.
  • R v O’Brien: Prosecution of ‘Britain’s Most Wanted’ for murder following an unprovoked stabbing in a nightclub. Deanna has been involved in many cases involving allegations of stabbing and shooting resulting in death.
  • R v Peters: Murder of a child by her father who strangled her. Another case involving complex psychiatric evidence
  • R v Baker and Wiltshire: The killing of a baby by her parents who then staged her death on a London bus. One of many cases Deanna has appeared in involving the killing of children including cases of so-called baby shaking syndrome.
  • R v Darbyshire: The mercy killing of a father by his daughter. The case required consideration of the legal issues relating to assisting suicide, manslaughter by suicide pact and murder.


Serious crime and fraud

  • R v SC: Instructed to defend a man accused of coercive and controlling behaviour by allegedly refusing to provide his wife with a “Get” (religious divorce). Deanna, leading Catherine Rabaiotti, successfully applied for the charges to be dismissed and stayed as an abuse of process. A subsequently appeal to the Court of Appeal by the prosecution was abandoned.
  • R v Beere and Payne [2021] EWCA Crim 432: Multi-handed conspiracy to import 250 tonnes of cocaine by fishing boat. Deanna has successfully resisted multiple appeals by the convicted defendants.
  • R v Stanislaus and others: conspiracy to launder £30m by central London bureaux de change.
  • R v Owen and others: multi-handed conspiracy involving UK wide misrepresentation within the egg marketing industry – passing off battery farmed eggs as free range/organic to national supermarkets.
  • R v Dandash and others; R v El Jamal and others: Multi-million banking frauds involving the creation of numerous accounts in false identities.


Health and safety

  • R v Tangerine Confectionary Limited and Veolia (ES) UK Ltd [2011] EWCA Crim 2013: Leading case in which the Court of Appeal clarified the relevance of foreseeability in proving statutory breaches.
  • R v BMI Healthcare and others: Multi-handed prosecution of four companies following the electrocution of a service engineer at a private hospital.
  • R v Segro Administration Limited and others: Multi-handed prosecution of six companies for offences arising from an accident at a freight handling centre near London Heathrow.
  • R v MACE and others: contested prosecution of three corporate defendants following the death of a traffic marshal during the redevelopment of the BBC Television Centre.
  • R v Clancy Docwra and Walsh: Successfully prosecuted both an employer and their employee following death of a ground worker during works to expand the Docklands Light Railway.
  • R v TDC: Defending a District Council following an outbreak of legionella at their public leisure centres which resulted in a member of the public becoming infected. Following mitigation, the fine imposed was less than 10% of the starting point within the guidelines.
  • R v Oxleas NHS Trust: Prosecution arising out of an incident at a medium secure mental health unit, in which a patient took a knife from the kitchen, stabbed two nurses and set fire to the ward.
  • R v BFK (Bam Ferrovial Kier): Prosecution of an unincorporated joint venture following a fatal accident during the Crossrail construction project.
  • R v Adsett and others: Contested prosecution of three corporate defendants and four individuals following the death of a woman who was killed when heavy window frames fell onto her as she walked through London’s West End.
  • R v University College London [2018] EWCA Crim 835: The prosecution of a university following an explosion at a laboratory which resulted in a student losing the sight in one eye. An appeal against sentence was successfully resisted in the Court of Appeal.
  • R v Falcon Crane Hire Ltd: Successful prosecution of breaches arising from the ‘Battersea Crane Collapse’ which resulted in the death of two people. Deanna also represented the HSE before the Coroner’s Court.
  • R v London Waste Ltd [2014] EWCA Crim 1954. The successful prosecution of a statutory breach which was contested in the Crown Court. Deanna also represented the HSE before the Court of Appeal, where the conviction was upheld.
  • R v Johnson [2009] 2 Cr App R(S) 28: Gross negligence manslaughter involving carbon monoxide poisoning [2009] 2 Cr App R(S) 28.

“One of the leading prosecutors who is very experienced. She is very talented”

“She really knows her stuff and is a terrifying opponent, in a good way.”

“She is a fantastic performer who takes full responsibility for the case”

Chambers and Partners (Crime) 

“Hardworking, thorough and with sound strategic instincts.”

“She has a strong background in dealing with serious crime.”

Legal 500 (Crime) 

“She really is first class on a complex case”

"She is an utterly superb advocate and has a razor-sharp intellect." 

"An excellent lawyer and jury advocate, with an amazing style: I would certainly not want to be prosecuted by her."

Chambers and Partners (Health and Safety) 

“Deanna has the law at her fingertips and possesses a relentless and steely determination”.

"Her knowledge of the caselaw and regulation is highly impressive."

“Her calm manner reassures clients.”

 Legal 500 (Health and Safety) 


Called 1994

Recorder of the Crown Court 2009

Junior Treasury Counsel 2015

King’s Counsel 2022

Senior Treasury Counsel 2022