Incoming MI6 chief’s grandfather was Nazi spy known as ‘The Butcher’

The family link was uncovered after the Daily Mail found hundreds of pages of documents in an archive in Freiburg, Germany, which showed that Dobrowolski was referred to as “Agent No 30” by Wehrmacht commanders.

The archive shows that Dobrowolski – born in Chernihiv in 1906 –vowed revenge against the Russians after soldiers murdered his land-owning family, plundered their estate and took control of Ukraine after the 1917 Bolshevik Revolution.

Within the files, there are hand-written letters from Dobrowolski to Nazi superiors, signed off “Heil Hitler”. There, he boasts of “personally” taking part “in the extermination of the Jews” and slaughtering hundreds of Ukrainian resistance fighters.

The files are said to suggest Dobrowolski looted the bodies of Holocaust victims and laughed while watching the sexual assault of female prisoners.

In one disturbing account from the German archive, Dobrowolski was said to be part of a police force that allegedly raped, shot and robbed the bodies of Jewish women in Ponornytsia, Chernihiv – though he is not believed to have taken part in the massacre and sexual violence.

He reportedly told commanders that he had organised a Ukrainian police unit of 300 men who “cleared” 12 sub-districts in Sosyntsia between October and December 1941, murdering the local Jewish population.

A witness, interrogated by the Germans more than a year later, said Dobrowolski’s subordinate handed to him “a gold watch” from one of the victims.

“I had access to [Dobrowolski’s] residence in Sosnytsia and saw many valuable possessions there, such as carpets, tablecloths, silk shawls, and a luxurious fur coat, which originated from the Jewish executions in Ponornytsia,” the witness said.

The same witness said that he “overheard” a conversation in which Dobrowolski “laughed” after being told “that female prisoners in the jail were being sexually abused through violence”. He reportedly said that he “tolerated these acts without objection,” according to the Daily Mail.

Beka Kobakhidze, a professor of modern history at Ilia State University in Tbilisi, Georgia, who uncovered the Metreweli family tree, said it was only a matter of time until the Kremlin “found and exploited the truth”.

“As a historian and researcher from a country that grapples daily with Russian propaganda, I can say with confidence that this will become a favourite talking point for Kremlin propagandists for years to come,” he said.

“Of course, children should not be held responsible for the sins of their fathers – or grandparents, for that matter. But I do find it puzzling why the UK would willingly hand such 'ammunition' to the Russians.”

But Metreweli, 47, never even met her grandfather, according to the Foreign Office, as he remained in Nazi-occupied Ukraine when the rest of his family fled after the Red Army’s liberation of the region in 1943.

Her father, Constantine Metreweli, is a British military veteran and renowned radiologist, who brought up his children in Hong Kong.

There was little trace of him in Britain, apart from an entry into the London Gazette in 1966 which reads: “Dobrowolski, Constantine (known as Constantine Metreweli); Of uncertain nationality.”

It transpired that, after the war, Dobrowolski’s wife Barbara fled to Britain with their two-month-old son, Constantine Jr.

She married David Metreweli in 1947 in Yorkshire, and Constantine Jr later took his stepfather's name of Metreweli. He went on to become a world-renowned radiologist and a UK armed forces veteran, before his daughter, Metreweli, was born in 1977.

“Blaise's ancestry is characterised by conflict and division and, as is the case for many with eastern European heritage, only partially understood,” a Foreign Office spokesperson said.

"It is precisely this complex heritage which has contributed to her commitment to prevent conflict and protect the British public from modern threats from today's hostile states, as the next chief of MI6."

They added that Metreweli "neither knew nor met her paternal grandfather".

Earlier this month, it was announced that Metreweli, who joined the Secret Intelligence Service in 1999, would take over from Sir Richard Moore in October and become MI6’s eighteenth chief.

Its chief, referred to as "C", is the only publicly named member of the service.

She grew up abroad before studying anthropology at the University of Cambridge, where she was in the winning crew in the 1997 Boat Race.

She is currently Director General "Q" – head of the technology and innovation division. She has previously held director level roles in MI5 – the UK’s domestic security agency – and spent most of her career in the Middle East and Europe.

At the time of the announcement, Foreign Secretary David Lammy said:“I am delighted to appoint Blaise Metreweli as the next Chief of MI6. With a wealth of experience from across our national security community, Blaise is the ideal candidate to lead MI6 into the future.

“At a time of global instability and emerging security threats, where technology is power and our adversaries are working ever closer together, Blaise will ensure the UK can tackle these challenges head on to keep Britain safe and secure at home and abroad.”