Inside the UK’s National Archives. Over 400 documents have reportedly gone missing, including a report on the British government’s involvement in Israel’s alleged nuclear arsenal. Photo: Wikimedia Commons.

Official documents relating to the British government’s involvement in Israel’s alleged nuclear arsenal have mysteriously gone missing, the BBC reported on Wednesday.

According to the report, over the last four years, 402 government documents have disappeared from the National Archives, including Foreign Office files from the 1970s and a letter written by former prime minister Winston Churchill in 1947.

One of the missing files listed includes a 1979 report entitled, “Military and nuclear collaboration with Israel: Israeli nuclear armament.” The lost nuclear report, the BBC said, apparently relates to a 1978 United Nations resolution highlighting concern over “increasing evidence” of Israel’s attempts to obtain nuclear weapons.

Since the 1950s, Israel has maintained a policy of nuclear ambiguity, neither confirming nor denying whether it possesses nuclear weapons.

Documents relating to city planning in Jerusalem during the time of the British Mandate also appear to be missing, the BBC said, including 23 photographs of plans and a “panoramic view of Mount of Olives; outer and inner city views,” as well as a 1918 memorandum by Sir William McLean, a civil servant and British architect, who submitted plans to develop Jerusalem while preserving the Old City, the report said.

The discovery of the missing documents came following a Freedom of Information request by the BBC. The National Archives said it was conducting a “robust” investigation into the missing documents, which remain unaccounted for since January 1, 2012.  

Historian and Labour MP Tristram Hunt, vice-chair of the All-Party Parliamentary Group on Archives and History, told the BBC that the missing documents are a “worrying loss.”

“The challenge is to ensure that you’ve got the systems to prevent that, because with every loss of a potential piece of archive you’re losing some history and understanding,” he said. “You’re losing a sense of connection and you’re losing the fabric of the past.”

Hunt said he was “particularly concerned” about the missing documents pertaining to Jerusalem, which he called a “fascinating period.”

The National Archives houses more than 11 million public records for the British government and distributes more than 600,000 documents each year. In 2011, it was discovered that 1,600 files were lost over the course of the previous six years.