British politicians defended Prince Charles' right to speak his mind after he reportedly compared the actions of Russian President Vladimir Putin in Ukraine to those of Adolf Hitler.
The heir to the throne made the apparently unguarded comment during a trip to a museum in Canada, in private conversation with a Polish-born woman who had fled the Nazis as a child.
"I had finished showing him the exhibit and talked with him about my own family background and how I came to Canada," 78-year-old Marienne Ferguson told the Daily Mail newspaper. "The prince then said: 'And now Putin is doing just about the same as Hitler'."
The remark made headlines around the world, and Russian media said it threatened to further "complicate" relations between Britain and Moscow.
Charles and Putin are both attending commemorations marking the 70th anniversary of D-Day on June 6, though royal aides said no formal meeting was scheduled.
Prime Minister David Cameron declined to comment on a private conversation, but said: "Of course, everyone is entitled to their private opinions."
Deputy Prime Minister Nick Clegg said the future king was "free to express himself".
Opposition Labour leader Ed Miliband went even further, saying: "I think he has got a point about President Putin's actions, and I think he is absolutely entitled to say that there are real concerns about that."
However, Labour lawmaker Mike Gapes, a member of the House of Commons foreign affairs committee, said the royals "should be seen and not heard".
He said on Twitter: "If Prince Charles wants to make controversial statements on national or international issues, he should abdicate and stand for election."
The prince's office would not confirm the remarks but said he would not have intended to make a political statement.
The prince reportedly made the remark during a tour of the Canadian Museum of Immigration in Halifax, Nova Scotia, as part of a four-day trip to Canada with his wife Camilla.
Ferguson, who moved to Canada with her Jewish family when she was 13 and who lost relatives in the Holocaust, confirmed her account of their conversation in a later interview with the BBC.
She added that it was "just a little remark - I didn't think it was going to make such a big uproar".
Members of the royal family by convention do not comment on political affairs, and Queen Elizabeth is famous for keeping her own counsel.
However, her son Charles, 65, has come under criticism in the past for his outspoken remarks about a variety of topics including architecture and genetically modified food.
There was no official reaction in Moscow to his comments, but the popular daily Moskovsky Komsomolets said the timing was "badly chosen" ahead of the D-Day commemorations.
Prince Philip undergoes minor medical procedure
Prince Philip, the 92-year-old husband of Queen Elizabeth, has undergone a minor medical procedure on his right hand but royal officials were quick to downplay any health concerns yesterday, saying he was attending a garden party.
A spokeswoman for Buckingham Palace said Philip, the duke of Edinburgh, underwent the procedure on Tuesday and meant his hand needed a bandage as protection. "It was a minor procedure and all his engagements will continue as planned. He is currently in the middle of a garden party," the spokeswoman said. She was unable to give any further details of the exact nature of the procedure or what was wrong.
Despite occasional illnesses, the sprightly duke continues to make regular public appearances as does the queen, 88, although she has cut back on long-haul flights and started to designate more official duties to the younger royals.
Philip, the longest-serving consort in British history, has won admirers for his charity work and support for the queen, but is as well-known for his sharp wit and verbal gaffes as he is for his devotion to duty.