Frances Hertzog


Specialising in serious organised crime and adept at dealing with cases involving complex telephony and forensic evidence, Frances is regularly instructed in large scale drugs, firearms and explosives conspiracies (both national and international), homicide, terrorism and all types of fraud.

Frances is renowned for her client care and has significant experience of dealing with vulnerable defendants in particular those diagnosed with Autism Spectrum Disorder and ADHD.

  • Organised Crime
  • Terrorism
  • Fraud


Criminal Defence

Frances is regularly instructed in large scale organised criminal conspiracies and specialises in cases involving drugs, firearms and explosives.

Her particular expertise is in dealing with telephone and other electronic evidence including cell-site and the use of encrypted (‘encro’) and spoof / tumbler phones. Frances defended in one of the first prosecutions arising from the international multiagency compromise of the ‘darknet market’ Silk Road.

She is frequently instructed in cases where a robust challenge to forensic evidence including low level DNA is required.

Frances is currently advising foreign nationals subject to extradition proceedings on allegations of multi-tonne international drug trafficking.


Notable Cases

R v M: Acted for the first defendant charged with the importation of multi-kilos of cocaine. Acquitted.

R v M: VHCC defence of multi-handed conspiracy to evade the prohibition on the importation and exportation of Class A drugs. FBI led investigation into trading on the dark web’s Silk Road site. Involved the review and analysis of 3 terabytes of data.

R v W: Defence of multi-handed conspiracy to supply Class A drugs throughout England, Wales and Scotland.

R v C: Defence of multi-handed conspiracy involving the seizure of in excess of 200kg of paracetamol and caffeine to be used in the adulteration of heroin. Acquitted. Proceedings stayed following 5 weeks of legal argument.

R v B: Defence of first defendant said to play leading role in a multi-handed conspiracy to supply Class A drugs in the North-East.

R v VM: Advising client in the Netherlands facing extradition proceedings in relation to a conspiracy to import 50 tonnes of Class A and Class B drugs into the UK.

R v O’M: Defence of multi-handed conspiracy to possess a firearm with intent to endanger life and conspiracy to pervert the course of justice. Defendant said to play the leading role in arranging and executing a shooting and thereafter orchestrating the planting of the gun in a rival’s vehicle together with 1 kilogram of cocaine.

R v M: Defence of multi-handed firearms conspiracy involving the discharge of a firearm into an occupied property and the towards the complainant following an assault.

R v P: Represented the first defendant in a multi-handed conspiracy to import firearms and ammunition from the United States. FBI led investigation.

R v B: Defence of multi-handed conspiracy to possess firearms with intent to cause fear of violence. Defendant said to have been participant in a gangland shooting.

R v W: Leading junior for the first defendant in a multi-handed conspiracy to possess explosives for an unlawful purpose and conspiracy to supply Class A drugs. Defendant said to have organised the planting of a hand grenade under a rival OCG member’s vehicle. Acquitted.

R v W: Defence of multi-handed conspiracy to cause explosions and conspiracy to burgle involving the theft of ATM machines throughout England and Scotland.

R v S: Defence of multi-handed conspiracy to steal and conspiracy to convert criminal property. Allegations of OCG stealing from cash machines nationwide at times using explosives.

R v B: Defence of allegation of attempted murder. Defendant alleged to be involved in an organised crime group responsible for the attempted murder of vulnerable individual with Autism Spectrum Disorder. S.28 cross-examination of the complainant. Acquitted.

R v M: Defence of multi-handed conspiracy to handle stolen goods (vehicles, parts and machinery) valued in excess of £1 million.

R v N, R v L: Trials in Leeds and Worcester where the defendants were alleged to be part of a gang hijacking lorries throughout the UK, kidnapping the drivers and stealing the contents. The Crown’s case relied on complex telephone and tracker data. Both cases stopped at the close of the Crown’s case.

R v A: Defence of multi-handed Child Sexual Exploitation grooming trial in Bradford. Complainants under the care of the Local authority.

R v O’D: Defence of multi-handed conspiracy to steal and burgle. Organised crime group stealing high powered vehicles.

R v L:  Defence of multi-handed conspiracy to kidnap, cause GBH with intent and blackmail. Acquitted.

Frances represents defendants at all stages of terrorism cases including pre-charge detention hearings.

She has represented defendants accused of a range of terrorism offences including encouraging terrorism, disseminating terrorist publications and possessing material likely to be useful for terrorism purposes, such cases often involving multiple terabytes of electronic data requiring thorough investigation and meticulous presentation at trial.


Notable Cases

R v G: Defence of allegations of possession of material likely to be useful for terrorist purposes. Involved the analysis of 11TB of data.

R v H: Defence of allegations of encouraging terrorism and disseminating and possessing material likely to be useful for terrorist purposes.

Frances defends those facing allegations of high value and complex frauds of all types including mortgage and tax fraud as well as those accused of disposing or concealing the proceeds of crime. She is known for her attention to detail and ability to marshal voluminous material.

Notable Cases

R v S: Defence of multi-handed money laundering and tax fraud. Included review and analysis of extensive self-assessment applications and the applicability of the Construction Industry Scheme regulations.

R v H: VHCC defence of former Company Director accused of multi-million-pound mortgage fraud. Included review, analysis and scheduling of extensive mortgage application documentation, company records, company e-mail traffic and mortgage company procedure. Review of complex issues under POCA including inter alia extensive bankruptcy documentation.


"Excellently well prepared and dedicated to the cause."Chambers and Partners, 2024
"She's an effective cross-examiner who's calm under pressure."Chambers and Partners, 2023
"Very committed and extremely patient with difficult and vulnerable clients."Chambers and Partners, 2023


Hertzog, Frances
Instruct FrancesTo instruct Frances please contact our clerks by phone on +44 (0) 20 7036 0200 or email us at