The Queen was dragged into the EU referendum debate last night amid claims she launched a lengthy criticism of European integration during a “bust-up” with Nick Clegg.

She is said to have “let rip” at the then Deputy Prime Minister during a lunch at Windsor Castle, where she is reported to have informed him of her belief that the European project was heading the wrong direction.

The “bombshell” claims, which appeared in the Sun, cited an anonymous “highly reliable source”, who said: “People who heard their conversation were left in no doubt at all about the Queen’s views on European integration. It was really something, and it went on for quite a while... The EU is clearly something her Majesty feels passionately about."

The newspaper's introduction reads: "The Queen was hailed as a backer of Brexit yestersday after details emerged of an alleed bust-up betwen her and Nick Clegg over Europe... A source said: 'People were left in no doubt about her views on Europe'".

However, buckets of cold water have been poured on the alleged conversation from five years ago.

Buckingham Palace denies it

Following the publication of the story, a Buckingham Palace spokesman said: “The Queen remains politically neutral, as she has for 63 years. We would never comment on spurious, anonymously sourced claims.

“The referendum will be a matter for the British people.”

Nick Clegg denies it

Mr Clegg said last night: “As I told the journalist this is nonsense. I’ve no recollection of this happening and it’s not the sort of thing I would forget.”

A spokesman for Clegg added: “This is categorically untrue. Nick has no recollection of this conversation and it is not the sort of conversation you forget.”

Page 2 virtually denies it

After being told that her Majesty “BACKS BREXIT”, an inside editorial, on page 2, then demands: “We must know her view”.

It adds: “The Queen is arguably the most respected stateswoman in the world. If she has a view on Brexit, don’t voters have a right to know what it is?

The one source did not say the Queen was backing Brexit

The claim, from the “impeccably placed source”, never mentions Brexit – as the reported lunch was in 2011. It is clear that you can be critical of the EU, without actually advocating a swift exit from the Union.

Many pro-EU politicians begin their defences of the European project with: “The EU isn’t perfect, but…”

...So, who was at the dinner?

A search of the Court Circular finds five people were present at a dinner attended by Nick Clegg and the Queen on April 7 2011 at Windsor Castle:

Nick Clegg, then leader of the Liberal Democrats

Michael Gove, then Education Secretary and now the Justice Secretary

Cheryl Gillian, then Secretary of State for Wales