The first museum dedicated to the life and times of Sir Winston Churchill has been opened by the Queen.
Winston Churchill directed British forces during World War Two
The £6m museum has been built in the underground Cabinet War Rooms, where the prime minister directed British forces during World War II.
Paying tribute to Churchill, the Queen said he had given the country "the hope, the courage and the confidence" to survive the war.
The museum opens to the public on Friday and is set to be popular.
Giving a short speech, the Queen said: "I am very pleased to be able to visit today the Cabinet War Rooms, the scene of Sir Winston Churchill's 'finest hour'.
"During those wartime years Churchill's determination and example gave us all the hope, the courage and the confidence to 'tread safely into the unknown'.
"It was the unique quality of his leadership that so inspired the British nation and free peoples throughout the world, as well as those suffering under Nazi occupation.
"That quality continues to inspire us today and should forever do so."
Churchill was recently voted by BBC viewers as the greatest Briton of all time.
The museum combines cutting edge technology, historical objects and thousands of images, film and sound recordings to convey the story of Churchill's 90-year life.
Grandson Winston Spencer Churchill, a former Conservative MP, said his grandfather would have welcomed the opening of the museum.
"He would have been absolutely delighted to know that 40 years after his death and 60 years on from the end of the Second World War, he is still not only remembered but honoured by his countrymen."
"I think few would deny he deserves it."
Winston Churchill was the Queen's first prime minister, when he returned to office for a second term in 1951.
Among those accompanying the Queen to the opening of the museum were Churchill's daughter, Lady Soames, his grandson and his wartime personal secretary, Mrs Elizabeth Nel.
"Churchill could be difficult and was rather impatient," said Mrs Nel, 87, who now lives in Port Elizabeth, South Africa.
"There was never enough time for all that he wanted to do.
"He stood firm and he never flinched.
"He set an example to the Allies, and in particular to the British, that what they had to do to survive was to give 100% effort and stand firm. And that, I think, was the measure of him."
Museum director Phil Reed said: "Churchill was an icon whose fame and significance still transcends class and generations.
"The young Queen Elizabeth II was present at Churchill's state funeral - the first for a commoner for over 100 years - and so it is a particularly poignant and historic gesture that she should open his museum."