Tributes have been paid to former US President Ronald Reagan, who has died at the age of 93.

His death, at a home in Los Angeles where he was surrounded by close family members, came after a long struggle with Alzheimer's disease.

President George W Bush offered his prayers and condolences to the Reagan family.

"A great American life has come to an end," he said.

During his presidency, which lasted from 1981 to 1989, President Reagan was credited with restoring American self-confidence while helping to bring about the demise of the Soviet Union.

He also formed a close relationship with former prime minister Baroness Thatcher, who described him as "a truly great American hero".

"He will be missed not only by those who knew him and not only by the nation that he served so proudly and loved so deeply, but also by millions of men and women who live in freedom today because of the policies he pursued," she said.

The Queen issued a statement saying she was saddened by the news.

And Downing Street said the prime minister had heard the news "with sadness".

"President Reagan will be remembered as a good friend of Britain," said Tony Blair's official spokesman.

"At home his vision and leadership restored national self-confidence and brought some significant changes to US politics while abroad the negotiation of arms control agreements in his second term and his statesman-like pursuit of more stable relations with the Soviet Union helped bring about the end of the Cold War.

"He will be greatly missed by his many friends and admirers on this side of the Atlantic."

Conservative leader Michael Howard told PA News: "This is an enormously sad day.

"President Reagan was one of the towering figures of our time, the man who with Margaret Thatcher won the Cold War for the West.

"It is so sadly ironic that he should have died as we prepare to commemorate the 60th anniversary of D-Day, the day when the allies began the liberation of Europe.

"We in Britain, as in so many other places around the world, owe him an ever-lasting debt. May he rest in peace."

And Liberal Democrat leader Charles Kennedy offered his "deepest sympathies" to Nancy Reagan and the American people.

"Irrespective of political viewpoints there is no doubt that Ronald Reagan restored America's belief in itself and the institution of the presidency," he said.