Tony Blair has said going to war over the Falklands took "political courage" and was "the right thing to do".
Tony Blair agreed the Falklands conflict had been a "scary gamble"
Interviewed for the Downing Street website the prime minister said there had been a "principle at stake".
Meanwhile, former Tory prime minister Margaret Thatcher is to visit a Vulcan bomber being restored for the 25th anniversary of the Argentine invasion.
The 74-day war, to be commemorated over the summer, claimed the lives of 255 Britons and 655 Argentines.
Argentina's invasion, on 2 April 1982, followed friction between the two countries dating back to 1833, when Britain claimed the islands in the south Atlantic.
But the British government decided it would fight to reclaim them and Mrs Thatcher dismissed advice from defence officials who feared the islands could not be re-taken.
She ordered a task force to be assembled to fight a war 8,000 miles away from the British Isles.
Speaking to the historian Simon Schama, in a website interview, Mr Blair agreed it had been a "scary gamble".
"But when I look back, yes, I have got no doubt it was the right thing to do," he said.
"But for reasons, not simply to do with British sovereignty, but also because I think there was a principle at stake which is that... a land shouldn't be annexed in that way and people shouldn't be put under a different rule in that way."
He noted that the British casualty figures were higher than those for the current conflicts in Iraq and Afghanistan.
"When you look back on it and you talk to the people who were there at the time, and as I say I wasn't even in Parliament at the time, but I think it took a lot of political courage actually to do that."
He added: "It was perfectly obvious there was only one way you were going to get it back, and that was by military action.
"And it was perfectly obvious also that irrespective of the debate about the Falklands, it was completely the wrong thing of General Galtieri to do and it was right to make it be reversed."
The islands are a British dependent territory, but Argentina maintains a claim to their sovereignty.
The 25th anniversary of the Falklands War will be marked by a series of events in the summer, including a veterans' march down the Mall in central London.
Events will begin with raising the Union flag in Port Stanley on 14 June, the day the conflict officially ended.
The victory greatly boosted the popularity of Margaret Thatcher's government, which went on to win the next election.
The head of Argentina 's military junta, General Leopoldo Galtieri, was deposed and served three years in prison for military incompetence. He died in 2003.