So - is the Queen pro-Brexit?
Queen Elizabeth has been canvassing opinion on the EU debate by asking dinner companions: "Give me three good reasons why Britain should be part of Europe."
Her biographer, Robert Lacey, reported the queen's comments and suggested they may mean she favours withdrawal from the European Union.
Buckingham Palace would not confirm whether or not she had been debating the merits of Brexit in private, but royal sources appeared to give credence to the report by saying the words attributed to the queen were "a question, not a statement".
However, the leading nature of the alleged question adds weight to previous claims that the queen would like Britain to pull out of the EU.
Last month, the UK's press regulator found that 'The Sun' newspaper had been guilty of "significantly misleading" its readers when it printed the headline "Queen backs Brexit" above a story about her complaining about Brussels to Nick Clegg.
One royal insider said of the latest report: "She appears to be asking a question, not making a statement. She is not expressing a view."
Queen Elizabeth is, officially at least, politically neutral, but she intervened in the Scottish referendum debate in 2014 by suggesting in a conversation with a member of the public, which she knew was likely to be reported by the press, that she hoped Scots would "think very carefully" before voting.
It was seen as a clear indication that she wanted Scotland to remain part of the United Kingdom.
Mr Lacey made his claim about the queen questioning dinner guests in a blog for the 'Daily Beast' website.
He told 'The Telegraph': "She asked the question in the context of a general debate - she loves a bit of forthright discussion and this sort of remark is tossed around the dinner table like a ping pong ball. That is the way she frames her questions."
A spokesman for Buckingham Palace said: "We would not comment on private conversations the queen may or may not have had, but the queen is above politics, has remained politically neutral for the 64 years of her reign and we are very clear that the EU referendum is a matter for the British people."