Historians are locked in a bitter row over a so-called “lost report” detailing the extent of Nazi crimes on the Channel Island of Alderney.

Marcus Roberts, founder and director of JTrails, a heritage group which specialises in Anglo-Jewish history, claimed to have uncovered information showing that the Nazis’ true intention was to use the island as a site for ‘extermination by Labour’ — a form of death camp — and that the number of Jewish dead buried there was much higher than had been previously estimated.

Mr Roberts also claimed that the complete version of the British government file, which is known as the Pantcheff Report, was embargoed in the UK until 2045 and that the unredacted copy he obtained from a Moscow archive contained explosive new details.

However, Professor Caroline Sturdy Colls, professor of Conflict Archaeology and Genocide Investigation at Staffordshire University, who has written a soon-to-be published book on the Nazi Occupation of Alderney, said the entire Pantcheff Report has been available in the UK National Archives since at least 2009. She added, “since 1993, the copy in the Russian archives has been used by researchers to describe the terrible crimes perpetrated against the forced and slave labourers on Alderney.” Claims about the report being “long lost” or “classified” had allowed some people to continue to “deny and downplay” the fact that the Holocaust that took place on the island, she said. Prof Sturdy Colls has now published the entire report from the UK National Archives online.

Two weeks ago, Mr Roberts released a statement saying he could “finally reveal the secrets of the actual ‘Pantcheff Report’”.

He added: “We have implicit official recognition that the key intention of the Nazis on Alderney was the mass deaths of prisoners through the Nazi policy of ‘extermination by labour’, by using officially sanctioned and systematic starvation, ill-treatment and executions.

“Certain island historians I have encountered have always denied this narrative (and that there was no concentration camp on Alderney) and this can no longer be sustained”.

Dr Gilly Carr, senior lecturer and academic director of archaeology at Cambridge University and the representative for the Channel Islands in the UK delegation of the International Holocaust Remembrance Alliance, weighed in against Mr Roberts, saying that not only had she seen the entire Pantcheff Report but that its revelations about the extent of Nazi atrocities on the island had been “discussed and published by a number of scholars to date.

“This is why, in 2019, I chose to work with Alderney in an IHRA project I chair, which seeks to safeguard all Holocaust sites,” she said.

Mr Roberts passionately responded: “I assert that some of this content appears not to have been seen before, or even if seen, to have been commented on before, or even if so, its significance has not been fully understood but which are particularly important now that we read them in the context of modern Holocaust scholarship”.

Mr Roberts claimed that, while 95 per cent of the contents in the Pantcheff Report are available elsewhere in the public domain, the previously unpublished five per cent shows that the numbers of Jewish dead on the island could have been more than 3,000.

He also added that one of the “secrets” in the Pantcheff Report are eyewitness accounts of “between 30 and 80 Jewish mass graves” in “one or more locations” on Alderney.

Prof Sturdy Colls’ archival and non-invasive archaeological research has also shown that unmarked mass and individual burials existed on the island. However, she argues that “while undoubtedly there are Jewish and non-Jewish victims who remain unidentified, I have yet to see any convincing evidence that would suggest that 30-80 Jewish mass grave pits exist. This claim appears to be based on a statement made by one witness who Pantcheff concluded in his report was unreliable”.

Prof Sturdy Colls has argued for more than a decade that there were many more deaths on Alderney than the previously accepted official figure.

Her research – based on a detailed comparison of surviving death certificates, burial records, witness testimonies, aerial photographs and the results of non-invasive surveys of the main cemetery used to bury the labourers — suggested a “conservative minimum” of between 650 and 950 deaths.

Lord Pickles, the UK Envoy on Post Holocaust Issues, this week wrote to the States of Alderney confirming that the documents in question were widely known by scholars and are available in the UK archives. He said: “In a world where Holocaust denial, distortion and revisionism in on the increase, we have a duty to provide the unvarnished facts. I believe the best way forward is to ensure that all documents, photographs and other materials relating to this dark period of history are published.

“I would urge that any WWII documents which remain ‘classified’ on Alderney should be opened to researchers. I look forward to working together to safeguard the truth of the historical record.”