Tony Blair won widespread praise yesterday for defending Kosovo, fighting global warming and overseeing peace in Northern Ireland - but he earned scant respect for championing the invasion of Iraq.

US President George Bush said he would miss the Prime Minister, his close ally in the Iraq war which followed soon after the invasion of Afghanistan in response to the 9/11 atrocity.

He heaped praise on Mr Blair, calling him "a man who kept his word, which sometimes is rare in political circles."

He added: "When Tony Blair tells you something, as we say in Texas, you can take it to the bank. He is a remarkable person, and I consider him a good friend."

Earlier, Tony Snow, White House press secretary, said Mr Blair had been an "extraordinary leader of the United Kingdom".

He and Mr Bush are "strong friends and allies, but also the Prime Minister has demonstrated the ability to work with presidents of both parties. We certainly appreciate everything he has done," Mr Snow added.

Republican Senator John McCain took time out from campaigning for president to pay tribute to Mr Blair. Mr McCain is the strongest advocate of Mr Bush's Iraq policy among major candidates for the presidential nomination in 2008, and he noted Mr Blair's contribution to the cause.

"I was not philosophically in tune with Prime Minister Blair because he is of the Labour Party, but I will always be grateful to Prime Minister Blair for his steadfastness on the issue of Iraq and Afghanistan," Mr McCain said.

Mr McCain said the British people had contributed and sacrificed "enormously" to the war effort and added: "Tony Blair literally sacrificed his political career for what he believed in. He will have my eternal respect and admiration."

At the State Department, spokesman Sean McCormack hailed Mr Blair as a good friend of the American people and "a terrific leader" for his country. He said Secretary of State Condoleezza Rice had had an excellent working relationship with Mr Blair.

"He is a staunch defender of freedom," Mr McCormack said.

He said the US would work closely with Mr Blair during the six weeks left of his term in office and with his successor. Mr McCormack said that Ms Rice knows Mr Brown, noting that the two attended a dinner recently when Mr Brown was in Washington for World Bank meetings.

Former US President Bill Clinton said: "Blair revitalised his party, modernised his country's economy and its approach to social problems, took the lead on global issues from climate change to debt relief to doubling aid to Africa, to the quest for peace in Northern Ireland and Kosovo, and started the global Third Way political movement.

"I am glad he was there and grateful for our friendship."

Jose Manuel Barroso, president of the European Commission, said: "Tony Blair has taken Britain from the fringes to the mainstream of the European Union.He leaves an impressive legacy including his commitment to enlargement, energy policy, action against climate change, and for fighting poverty in Africa."

But many viewed the Iraq war as a serious mistake by Mr Blair and criticised him for not questioning the US insistence on toppling Saddam Hussein.

Swedish Prime Minister Fredrik Reinfeldt called Mr Blair a "jovial, easy-going person" and a "fantastic speaker".

Staying in office for 10 years was a major accomplishment, he said. "And to do it in a country with the British press is an accomplishment in its own right," he added.

Mr Reinfeldt said the Iraq war led to Mr Blair's eventual demise and that his decision to join the 2003 invasion was likely influenced by the notion that "every British Prime Minister has a historical duty to be very close to the American administration".

"It is no easy task to make fundamentally different policy assessments (from the US) on important foreign policy matters," he said.

Former US Secretary of State Colin Powell, who helped lead the US push for war, said: "He has been steadfast in the face of negative public opinion and in the face of crises he's stood steady. And we could always count on him."

In India, Mr Blair won praise for supporting its bid for a permanent seat on the UN Security Council.

K Subrahmanyam, a former member of India's National Security Council and a leading defence analyst, said: "He was able to achieve the Northern Ireland peace agreement. There is quite a lot for him to take credit for." He added, however: "Iraq is perhaps the worst blunder."

In Kosovo, Mr Blair is credited with leading and building international consensus to stop the crackdown by Serb forces on the ethnic Albanian majority in 1999.

When he visited the province soon after British forces deployed in Kosovo following the war, hundreds of thousands of ethnic Albanians gathered to thank him. Ulpiana Lama, Kosovo's government spokeswoman, said: "We are grateful and thankful for his extraordinary contribution. He made the Kosovo issue in 1999 a priority of foreign policy."

Japanese Prime Minister Shinzo Abe praised Mr Blair's record on education and economic development.

Danish Prime Minister Anders Fogh Rasmussen said Mr Blair had helped make Britain "one of Europe's best-functioning economies".

EU foreign policy chief Javier Solana expressed hope that Mr Blair's successor would be "good for his country, no doubt, but also good for Europe. I think that Europe is going through a very important moment".

French President Jacques Chirac, who had rocky relations with the Prime Minister, made no statement but was due to play host to Mr Blair in Paris today.

He "will receive the Prime Minister and tell him directly the price that France attaches to its relations with the United Kingdom," an aide said.

The departure of the two leaves Europe with new management in two of its biggest economic, military and diplomatic powers. Mr Blair has better relations with Nicolas Sarkozy, taking over from Mr Chirac next week, and will also meet with Mr Sarkozy today.

John Nagenda, a senior adviser to Ugandan President Yoweri Museveni, said Mr Blair's efforts to fight poverty in Africa - another of his major policy initiatives - had produced little.

"He created high-sounding committees full of celebrities but if these ever translated into concrete actions, they passed me by and I'm a wide awake kind of guy," he said, calling Mr Blair's departure "a very overdue move".

In 2006, Britain was among several wealthy nations that cut millions in aid to the Ugandan government, saying that Mr Museveni had mishandled the transition to multiparty politics.