Tony Blair and Michael Howard last night led tributes to Sir Edward Heath who has died aged 89.
The Prime Minister said: "He was a man of great integrity and beliefs he held strongly from which he never wavered.
"And he will be remembered by all who knew him as a political leader of great stature and significance."
Tory leader Mr Howard said: "Ted Heath was one of the political giants of the second half of the 20th century.
"He was the last Conservative leader who had served in the Second World War."
Sir Edward was well enough to celebrate his 89th birthday with a party only last week.
But he had " recently become considerably weaker", a spokesman said.
The ex-Prime Minister had been "resting quietly" at the Salisbury home he loved when he passed away at 7.30pm.
Sir Edward suffered a pulmonary embolism while holidaying in Australia two years ago and never seem to recover fully.
Although in Downing Street for less than four years, his legacy is assured as the leader who took Britain into Europe.
He will be equally remembered for his long feud with Baroness Thatcher, who ousted him as leader. His reaction was memorably described as the "longest sulk in history".
The son of a housemaid and a carpenter, he became the Tories' first working class Prime Minister in 1970.
Although he secured UK membership of the Common Market, his time in No 10 was also marked by a confrontational approach to pay and the unions which resulted in numerous strikes.
With the country on a three-day week and rubbish piling up in the streets the miners threatened to bring his government down.
In 1974 Sir Edward called an election asking "who governs Britain?" and did not get the answer he had hoped for.
The knives were out and junior colleague Margaret Thatcher surprised everyone defeating him in a leadership contest the following year, ending 11 years at the top of the party.
His great political rival Baroness Thatcher said Sir Edward was "a political giant", "the first modern Conservative leader" and "we are all in his debt".
Former Labour MP Tam Dalyell, who succeeded Sir Edward as Father of the House, praised him for not " going cap in hand to Washington".
"He stood up to American views and wasn't just enchanted by the White House lawn as so many others were."
Mr Dalyell said he had forged a bond with Sir Edward as a Labour rebel backing him over Europe.
He said the "long sulk" was because he did not believe in Baroness Thatcher's view of "them and us" politics.
"He had been in the war and you know if you have fought alongside men and women of different political views you come to respect them and listen to what they have to say," he said.
Two former Cabinet colleagues, Lord Prior and Lord Walker, recalled a very kind and "delightful" man.
Lord Prior said: "I am very sad that the end has come but he had a good life and a long life and achieved a great deal.
"He didn't achieve all that he wished for himself or that we wished for him, but perhaps he was ahead of his time."
Lord Prior said Mr Heath feared that when Margaret Thatcher took over, the party would move away from the centre ground and too far to the right.
"It took a few years for that to happen but it has happened and look at the result now," he said.
"He was never frightened of speaking out, he always stuck to his line, he was a very courageous man and he was a very talented man."
Describing the man behind the public figure, he said: "The man I knew was a much more sensitive man than most people realised I think.
"He cared desperately about people and about the doing the right thing for the country - he was a great patriot.
"He was a delightful man in private. He had a very lively sense of humour, but in private he was a very, very good host, a very good friend and a very loyal friend.
"I think history will treat him rather more kindly than the present."
Lord Walker said: "I think history will give him a very high rating.
"He was a very great man, above all he was an enormous patriot."
"His definition of patriotism was he wanted everybody to be born a citizen of your country to rejoice in being born a citizen in that country."
Liberal Democrat leader Charles Kennedy said: "With the passing of Sir Edward Heath, our country has lost a gifted, good and indeed great figure.
"There can be few of whom it can be said that they literally changed the course of history but undoubtedly, where Europe is concerned, that can be said of Sir Edward Heath," he added.
"When I became Liberal Democrat leader, Sir Edward and I always maintained personal and political goodwill, both of which I much appreciated."
Ex-Cabinet minister Lord Brittan said Sir Edward had been "absolutely determined to take us into what was then the Common Market because he thought that was what was right for Britain".
The former European Commissioner said: "One should also remember he saw the need for reform of things in this country and tried to do what Margaret Thatcher did later.
"He was less successful because people were not ready for it. Things had to get better before people were ready to accept those reforms.
"However, he had a very similar vision - although perhaps neither he nor Margaret Thatcher would have wished to recognise that.