Amnesty International has called for an “exhaustive” investigation into the death of a British civil defence worker who fell from a balcony in Istanbul just days after Russia accused him of being a spy.

The body of James Le Mesurier, an ex-British army officer and UN peacekeeper who co-founded the White Helmets in Syria, was found near his home in the Turkish city on Monday morning.

Last week, Russian Foreign Ministry spokeswoman Maria Zakharova accused Mr Le Mesurier of being a former British agent working in the Balkans and the Middle East.

She claimed he had “been spotted all around the world, including in the Balkans and the Middle East”.

“Given the role of the West in undermining stability in these regions, it is not difficult to assume what the British intelligence officer did there,” she said.

Amnesty International said on Tuesday that there was a possibility of foul play.

Kristyan Benedict, the human rights group’s Syria campaign manager, said: “There needs to be an exhaustive investigation into the full circumstances of Mr Le Mesurier’s tragic death, which has shocked the entire Syrian humanitarian community.

“In helping to establish the White Helmets, Le Mesurier was instrumental in saving the lives of thousands of Syrian civilians.

“The brave men and women of the White Helmets have repeatedly risked their own lives to dig people out of the rubble after devastating Syrian government and Russian air strikes on homes, marketplaces and hospitals.

“Given the long history of smears and accusations made against Le Mesurier and the White Helmets, the possibility of foul play must surely form part of the Turkish authorities’ investigation into his death.

“We will be watching the outcome of Turkey’s investigation into Mr Le Mesurier’s death very closely.”

James Le Mesurier
James Le Mesurier (AP)

Dame Karen Pierce, the UK’s representative to the United Nations, also said the UK would be “looking closely” at Turkey’s investigation.

“We will be looking very closely to see how the investigation goes. I hope the Turkish authorities will be able to investigate thoroughly, and I’m sure we’ll want to give them any assistance they might require,” she said.

“I do just want to take the opportunity though to say on the record that the Russian charges against him, that came out of the Foreign Ministry that he was a spy, are categorically untrue.”

The Istanbul governor’s office said “comprehensive administrative and judicial investigations into Le Mesurier’s death have been initiated”.

Turkey’s state-run Anadolu news agency said police established that no-one had entered or left Mr Le Mesurier’s home at the time of the incident, and believe he may have fallen to his death.

His body was found near his home in the Beyoglu district by worshippers on their way to a mosque, according to reports by Anadolu.

Anadolu also said Mr Le Mesurier’s wife told police that her husband had been taking medicine to treat “intense stress”.

Mr Le Mesurier was the founder and chief executive of May Day Rescue, which founded and trained the White Helmets, also known as the Syria Civil Defence.

The White Helmets group confirmed his death on its Facebook page, and offered “deepest condolences” to his family.

It urged the media to “refrain from unnecessary speculation about the cause of his death until the investigation is completed”.

It added: “We ask that James be remembered as what he was: a great leader, a visionary, and a dear colleague and friend.”

The group, which has had more than 3,000 volunteers in opposition-held areas, says it has saved thousands of lives since 2013 and documented Syrian government attacks on civilians and other infrastructure.