Jonathan Polnay KC

Admired and sought after, Jonathan Polnay KC is a standout criminal advocate

Overview

Jonathan Polnay KC is a truly outstanding criminal barrister and recognised as being at the very top of the profession. He was appointed Senior Treasury Counsel in 2024, having been a junior since 2017 and is regularly instructed in the most serious and high-profile cases, accepting instructions on behalf of both the prosecution and the defence. 

Experience

Jonathan has been instructed in some of the highest profile criminal cases, including the murder of Sir David Amess MP, the ‘black cab rapist’ John Worboys, the killing of PC Harper, and the manslaughter of 39 Vietnamese migrants. 

Jonathan is known for his fierce intellect, commitment, diligence, and easy manner; he is much admired for his excellent strategy and incisive judgment, his encyclopedic legal knowledge and ability to communicate complex evidence in a way that is clear and attractive to juries.

Jonathan accepts instructions from all specialist divisions of the Crown Prosecution Service, a vast array of defence solicitors and where appropriate, via Direct Access.

Notable Cases

R v. Long and ors [CCC] (2020)
Prosecution of three men for killing a Thames Valley police officer
Jonathan Polnay was instructed in the prosecution of three young men for killing PC Andrew Harper, whilst trying to escape with a stolen quad bike.
BBC report here

R v Robinson and ors [CCC] (2020)
39 counts of manslaughter of Vietnamese migrants 
Jonathan Polnay prosecuted the manslaughter of 39 Vietnamese migrants who suffocated to death in a shipping container whilst being smuggled in to the UK.
BBC report here

R v. Theodore Johnson [C.C.C] (2018)
Prosecution of man for third offence of homicide of his partners Jonathan Polnay acted for the Crown in the case of Theodore Johnson who was sentenced to life with a minimum tariff of 26 years, increased on appeal against Unduly Lenient Sentence, to 30 years in March 2018. Johnson had been convicted previously for the manslaughters of his partners in 1981 and 1993. His third victim, Angela Best, was murdered with a claw hammer in her flat in North London in December 2016. 
News report here

Operation Boldo [I.L.C.C.] (2017)
Horsemeat Fraud 
Jonathan Polnay was lead Counsel for the Crown in this multi-handed and much publicised conspiracy involving three prominant businessman passing off horsemeat as 100% pure beef.
News report here

R v. Patel [Southwark] (2014)
First ever prosecution for Acquiring Biological Weapons 
Jonathan Polnay prosecuted a women who was charged with the first ever prosecution under the Biological Weapons Act and attempted murder of her mother, after attempting to poison her, taking her inspiration from the series "Breaking Bad".
News report here.

Operation Cent [C.C.C.] (2013)
Anti-corruption unit worldwide investigation re: bomb detection units
Jonathan Polnay represented a defendant in the much publicised Old Bailey trial involving the worldwide sale of "fake" bomb detection devices. Instructed by Gary Bloxsome of Blackfords LLP.
BBC news report here

Reviews

Chambers UK 2025: Crime - New Silks Band 1

Legal 500 2025: Crime - New Silks Band 1

Legal 500 2025: Fraud Crime - New Silks Band 1

'He is completely formidable and brings detailed understanding. He has a vast appetite for hard work.' Chambers UK (2025)

'Jonathan is very well prepared with strong tactical sense and an encyclopaedic knowledge of the law. These qualities made him a formidable junior and will make him a great silk.' Legal 500 (2025)

'He's a superstar on the rise.' Chambers UK (2024)

'He's exceptional in terms of his legal ability and the way he deals with tribunals and co-counsel.' Chambers UK (2024)

'Jonathan is at the very top of the profession, an excellent advocate and lawyer. He is a class act: fair, hardworking, and clever. He is in so many ways just an ordinary bloke but he has an extraordinary talent.' Legal 500 (2024)

'He is outrageously good and instils total confidence from the outset. A hugely impressive professional who is very, very responsive and able to grasp cases immediately.' Chambers UK (2023)

'Jonathan is immensely impressive. He is incredibly clever, extremely hard working, and thinks incredibly quickly on his feet. A lethal cross-examiner.' Legal 500 Financial Crime (2023)

'Jonathan's legal knowledge and tactical acumen are second-to-none. He is a formidable advocate both on paper and on his feet.' Legal 500 (2023)

'He is highly intelligent; he is prolifically hard-working and has endless stamina and he is a great strategist and his judgment is pretty perfect. He is one of the best junior Treasury Counsel at the Old Bailey. A masterful advocate; he makes winning look easy.' Legal 500 (2021)

'Has the ability to simplify complex prosecution cases that might be strong evidentially but are on paper difficult to communicate to a jury.' 'He is good with the jury and is also someone whose judgement you can trust.' Chambers UK (2021)

'He has extensive experience of how the criminal justice system operates in practice, particularly in relation to the processes used by law enforcement and the mechanics of the various powers available to law enforcement agencies. He has excellent judgement and is able to offer simple, but highly useful suggestions.' Chambers UK (2020)

'There are not enough superlatives to do this gentleman justice; he has a prolific energy that galvanises his cases.' Chambers UK (2019)

'He instils great confidence in clients.' Legal 500 (2016)

'A very effective prosecutor, and also a very hardworking defence junior, who gets on very well with clients.' Legal 500 (2017)

'A masterful advocate – eloquent, sharp and irresistibly persuasive.' Legal 500 (2020)