Queen: '˜it would be awkward not to shake hands' with Martin McGuinness

The meeting between the monarch and the former IRA commander took place at the Lyric Theatre in Belfast in June 2012 at an event organised by Co-operation Ireland.

It was viewed as a highly symbolic gesture at the time but, according to a new book by the Daily Mail features writer Robert Hardman, Queen Elizabeth II told then prime minister Mr Cameron that she did not know what “all the fuss was about”.

Former deputy first minister Mr McGuinness reportedly spoken to the Queen in Irish, with a greeting translating to “goodbye and God bless”.

Mr Cameron described to the book’s author how he told the Queen: “I think it was the most transformative bit of diplomacy I have seen. It was amazing.”

Despite this, Mr Cameron said, the Queen was “as ever not sure what all the fuss was about”.

In the book, he described the monarch as having been slightly embarrassed by the adulation she received for meeting “the leader of an organisation that had once been hell-bent on exterminating her entire family”.

In 1979, a favourite cousin of Queen Elizabeth II, Lord Louis Mountbatten, was killed by an IRA bomb while on holiday in Co Sligo. The bombers had attached a bomb to a fishing vessel which exploded no more than five minutes after it had left the harbour.

The IRA blast also claimed the lives of two youngsters who were on the vessel – the peer’s 14-year-old grandson, Nicholas, and an Ulster schoolboy, Paul Maxwell, from Enniskillen.

According to Mr Hardman’s book, entitled ‘Queen of the World’, the Queen had asked David Cameron of the historic handshake: “What was I meant to do?

“Of course I shook his hand. It would be awkward not to.”

The handshake with Mr McGuinness, who had admitted to being a former IRA commander, was described at the time as “wonderful” by Countess Mountbatten, a former lady-in-waiting to the Queen whose father and son were murdered by the IRA in the 1979 bomb attack.

Speaking to the Daily Telegraph at the time, she added: “I’m hugely grateful that we have come to a point where we can behave responsibly and positively.”

The book, which is being serialised in the Daily Mail newspaper, also reports that the Queen’s famous speech on her 21st birthday was in fact pre-recorded.

Mr McGuinness died in January last year.