Nick Clegg has accused Brexit supporters of trying to "drag" the Queen into the EU referendum debate, after a newspaper reported claims that she had voiced strong Eurosceptic views during a lunch with the former deputy prime minister.
The Sun quoted an unnamed "senior source" as saying that the Queen vented her anger with Brussels at Mr Clegg during a Windsor Castle lunch in 2011.
But the report was dismissed as "nonsense" by the former Liberal Democrat leader, while Buckingham Palace insisted the Queen is "politically neutral" in the EU referendum campaign.
The source quoted by The Sun said that people who heard the lunch 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 source was quoted as saying.
But Mr Clegg told ITV's Good Morning Britain: "It is not true. I have certainly, absolutely no recollection of a conversation like that, which I suspect I would have remembered if it had taken place."
And he added: "I just think it's wrong that people who want to take us out of the European Union to now try and drag the Queen for their own purposes into this European referendum debate."
A spokesman for Mr Clegg confirmed that the former DPM had lunch with the Queen on a number of occasions during his five years in office, but was unable to say how many of them took place during 2011.
In his role as president of the Privy Council, he attended nine meetings of the body at which the Queen was present during 2011, but all took place at Buckingham Palace except for one at Windsor Castle on April 7.
It is not clear whether this meeting included the lunch reported in The Sun. Privy Council meetings often take place in the late afternoon and do not usually involve a meal. But a court circular records that the April meeting happened at 12.40pm, leaving open the possibility - which has not been confirmed - that the Queen may have invited her guests to lunch before or after the formal session.
Also present at the April 7 meeting were fellow privy councillors Michael Gove and Cheryl Gillan - both advocates of a vote to leave the EU in the June 23 referendum - as well as Liberal Democrat peer Lord McNally.
A spokeswoman for Ms Gillan - who was Welsh secretary at the time - told the Press Association: "Ms Gillan has no comment to make on Privy Council matters." There was no immediate response to a request for comment from Mr Gove's spokesman.
A Palace spokesman said: "The Queen remains politically neutral, as she has for 63 years.
"We will not comment on spurious, anonymously sourced claims. The referendum is a matter for the British people to decide."
One Conservative MP backing UK withdrawal from the EU said he was "uneasy" about apparent efforts to use the Queen's supposed opinions to influence the referendum vote.
Conor Burns tweeted: "I'm more than slightly uneasy by attempts to try and drag the Queen into EU debate. Monarch shouldn't be used in divisive political debate."
Liberal Democrat former cabinet minister Sir Edward Davey said he was not present at the meal in question, but believed the claims about the Queen's alleged comment had "no credibility".
The former energy secretary told BBC Radio 4's Today programme: "I know Her Majesty believes in the United Kingdom, believes in Great Britain. And if we pull out of the EU, we will destroy our country because Scotland will go independent, the peace process in Northern Ireland will be under real pressure and we won't have something called the United Kingdom or Great Britain any more. I doubt the Queen wants that."
In June last year, a speech by the Queen in Germany was interpreted by some as expressing a pro-EU view.
During a state banquet in Berlin in the presence of German chancellor Angela Merkel and Prime Minister David Cameron, the Queen said "division in Europe is dangerous" and that the continent must strive to "maintain the benefits of the post-war world".
Buckingham Palace said then that the speech, on the eve of a Brussels summit, was not intended to make any political point about the future of the union.
"The Queen's speech speaks for itself on the threats of division and the benefits of unity," a Palace spokesman said at the time. "As ever, the Queen is above politics and is politically neutral on the EU.''