One of the UK’s most respected international criminal lawyers who was representing Wikileaks founder Julian Assange has died after being hit by a train in West Hampstead.

Married father of two John Jones, QC, worked at renowned legal chambers, Doughty Street and died last Monday morning. Police say they are not treating the death as suspicious.

The 48-year-old barrister has been described as “a giant in his field” by colleagues, who said that his death is “a monumental loss to the cause of international justice and human rights.”

Oxford graduate Mr Jones, who took silk in 2013, specialised in extradition, war crimes and counter-terrorism, representing clients from around the world in high profile cases.

He was part of a team of lawyers acting to prevent the extradition of Julian Assange - holed up in the Ecuadorian embassy for four years - whose case is currently being heard by the UN Working Group on Arbitrary Detention.

Mr Jones was also working with his colleague Amal Clooney to try and halt the execution of Colonel Gaddafi’s son Saif and Libyan spy chief Abdullah-al Senussi.

Earlier in his career, he helped bring to justice some of those responsible for genocide in the former Yugoslavia as part of the UN’s International Criminal Tribunal, working to establish procedures that were used in the historic trials.

As well as his criminal law work, Mr Jones acted as a human rights lawyer, saving a 19-year old from the death penalty in Singapore, fighting on behalf of journalists for free speech in Africa, and making representations to the UN to prevent torture.

He joined Doughty Street in 2005, where he worked alongside some of the UK’s top barristers, including Keir Starmer, MP for Holborn and St Pancras, who remains an associate tenant there.

Mr Starmer, who knew Mr Jones well, said: “John made a huge contribution to international justice. His loss is felt deeply by all his friends and colleagues, and all our thoughts are with his family and friends.”

Doughty Street Chambers said in a statement: “The passing of John Jones QC is a monumental loss to the cause of international justice and human rights worldwide. He was a pioneer, at the forefront of establishing our modern system of international criminal justice, and a giant in the field.

“John was a good friend, great colleague and a brilliant and creative lawyer.

“John was admired and appreciated for his amazing sense of humour, his professionalism and his deep commitment to justice and the rule of law.

“His death is a huge loss for all of us in Chambers, for the British and international legal profession, but mostly for his family to whom we offer our sincerest and deepest condolences.”

The statement also praised Mr Jones for his wit, eloquence and benevolence. His colleagues said: “John prepared humbler cases with a rigour equal to his higher profile ones. He constantly gave his services for free, and his generous spirit and selfless devotion came at some cost.”

Mr Jones lived in Kentish Town with his wife and two young children.

A statement from British Transport Police said officers attended West Hampstead rail station at 7.07 on Monday morning after a man was struck by a train.

It said: “He was pronounced dead at the scene. The man’s death is not being treated as suspicious. A file will be prepared for the coroner.”

Messages of support can be sent to condolences@doughtystreet.co.uk and cards or letters can be sent to Chambers (53-54 Doughty Street, WC1N 2LS) to be forwarded to the family.

A fund has been set up for his family, and donations can be made to the Doughty Street John Jones QC Memorial Fund (sort code 20-77-67, account no. 93017451.