More than 400 documents, including government files relating to the UK’s involvement in Israel’s alleged nuclear arsenal, have gone missing over the last four years, it has been revealed.

The response to a Freedom of Information request showed the UK’s National Archive at Kew contains more than 11 million documents in total, including many government documents that become publicly available after 30 years.

Notable missing files include 1970s documents on nuclear collaboration with Israel, as well as a letter from Winston Churchill.

The losses include more than 60 Foreign office files, over 40 Home office documents, and six from the records of former prime ministers.

According to the BBC, one MP from the parliamentary group on official archives said he was “concerned” by their loss.

The losses were revealed by a FoI request submitted by the BBC.

A 1979 document titled “Military and nuclear collaboration with Israel: Israeli nuclear armament”, is among the missing pieces.

The file, contained among government files on arms control and disarmament in the 1970s, apparently relates to a United Nations resolution from 1978 which concerned “increasing evidence” Israel was attempting to acquire nuclear weapons.

Since the 1950s, Israel has retained a policy of nuclear ambiguity, neither publicly confirming nor denying whether it has a nuclear arsenal.

However, Israel is now thought to possess 80 nuclear warheads, built up as western governments have “played along with the policy of ‘opacity’”, as the Guardian’s Julian Borger puts it.

Labour MP Tristram Hunt, the vice-chair of the All-Party Parliamentary Group on Archives and History, told the BBC the missing files were a “worring loss”, but added that the National Archives were among the world’s best and were run “incredibly effectively and efficiently”.

He said: “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.

In pictures: JFK's Cold War nuclear shelter Show all 10 1 /10 In pictures: JFK's Cold War nuclear shelter In pictures: JFK's Cold War nuclear shelter Kennedy-nuclear-shelter-2.jpg Curator Ruth Pelletier walks down a hallway in the cold-war era nuclear fallout shelter constructed for President John F. Kennedy on Peanut Island, Florida Reuters In pictures: JFK's Cold War nuclear shelter Kennedy-nuclear-shelter-1.jpg A cold-war era nuclear fallout shelter constructed for President John F. Kennedy is shown on Peanut Island near Riviera Beach, Florida Reuters In pictures: JFK's Cold War nuclear shelter Kennedy-nuclear-shelter-3.jpg The dingy, cavernous steel fallout shelter hastily built on a man-made island off Florida's east coast is a stark reminder of the harsh realities President John F. Kennedy faced from the first days of his presidency at the height of the Cold War Reuters In pictures: JFK's Cold War nuclear shelter Kennedy-nuclear-shelter-4.jpg Guests visit the cold-war era nuclear fallout shelter constructed for U.S. President John F. Kennedy on Peanut Island, Florida Reuters In pictures: JFK's Cold War nuclear shelter Kennedy-nuclear-shelter-5.jpg Short wave radios are shown in the cold-war era nuclear fallout shelter constructed for U.S. President John F. Kennedy on Peanut Island, Florida Reuters In pictures: JFK's Cold War nuclear shelter Kennedy-nuclear-shelter-6.jpg A hallway is shown with a generator at the far end in the cold-war era nuclear fallout shelter constructed for U.S. President John F. Kennedy on Peanut Island, Florida Reuters In pictures: JFK's Cold War nuclear shelter Kennedy-nuclear-shelter-7.jpg Bunk beds in the cold-war era nuclear fallout shelter constructed for U.S. President John F. Kennedy on Peanut Island, Florida Reuters In pictures: JFK's Cold War nuclear shelter Kennedy-nuclear-shelter-8.jpg A box containing a radiation detection kit is presented in the cold-war era nuclear fallout shelter constructed for U.S. President John F. Kennedy on Peanut Island, Florida Reuters In pictures: JFK's Cold War nuclear shelter Kennedy-nuclear-shelter-10.jpg General manager Anthony Miller stands in the cold-war era nuclear fallout shelter constructed for U.S. President John F. Kennedy on Peanut Island, Florida Reuters In pictures: JFK's Cold War nuclear shelter Kennedy-nuclear-shelter-9.jpg The emergency exit in the cold-war era nuclear fallout shelter constructed for U.S. President John F. Kennedy on Peanut Island, Florida Reuters

“You're losing a sense of connection and you're losing the fabric of the past.”

Another significant loss is a file containing a letter written by former Prime Minister Winston Churchill in 1947 during the time he wrote his account of the Second World War, which contributed to his Nobel Prize for Literature in 1953.

The missing documents account for a tiny percentage of all the files the National Archives holds.