The Deputy Prime Minister Nick Clegg has defended Prince Charles over his comments comparing Russian President Vladimir Putin to Nazi dictator Adolf Hitler.

The Prince of Wales was on a four-day visit to Canada, where he spoke to Marienne Ferguson, a 78-year-old working at Museum of Immigration in Halifax, who migrated to Canada with her family in 1939, but lost many of her relatives to Holocaust.

Ferguson was telling him that her family had to flee to Canada, shortly before Hitler invaded Poland.

To this, the Prince said, "And now Putin is doing just about the same as Hitler," according to Ferguson.

The Daily Mail reported that many witnesses heard his undiplomatic reply.

Mr Clegg said there was nothing wrong with him having views and expressing them, particularly in private, and said it was unrealistic to expect members of the Royal Family not to have opinions.

Mr Clegg told BBC Radio 5 live: "I certainly support his right to speak freely, particularly in conversations that are private."

Ms Ferguson's said: "I was very surprised that he made the comment as I know they [members of the Royal Family] aren't meant to say these things.

"I must say that I agree with him and am sure a lot of people do.

"I told the Prince that while my family and I were lucky to get a permit to travel, many members of my relatives had permits but were unable to get out before the war broke out on September 1.

"They were sent to the concentration camps and died."

A spokesperson for the heir to the British throne said: "We do not comment on private conversations. But we would like to stress that the Prince of Wales would not seek to make a public political statement during a private conversation."

Labour and Co-operative Party MP Mike Gapes, criticised Prince Charles alleged remarks on his twitter account.

"It is for Parliament and government to use appropriate language to condemn illegal annexation of Crimea. Prince should stop free lance foreign policy"

"If Prince Charles wants to make controversial statements on national or international issues he should abdicate and stand for election."

Prince Charles is scheduled to meet Putin in France on 6 June, for commemoration of the 70th anniversary of the decisive D-Day landings in Normandy, which were instrumental in liberating France from German occupation and bringing a swift end to WW II.