British Prime Minister Tony Blair (search), who has been under increasing political pressure because of the war in Iraq, was hospitalized Sunday with heart palpitations, his office said. Doctors restored Blair's normal heartbeat with electrical stimulation and he was feeling "fine" at home.

Blair, 50, was taken to London's Hammersmith hospital (search), treated and released after five hours, his office said. The prime minister was feeling "fine" after returning home, his office at No. 10 Downing Street said in a statement.

"This was completely successful. He was in hospital for four to five hours and is now back at Number 10. The hospital says this is a relatively common condition and is easily treated," it said.

"He has suffered no damage and he is fine. There is no reason why this should reoccur. They have advised him to rest for 24 hours."

Blair was expected to return to work full-time Tuesday, his office said. He will not make a planned statement to the House of Commons (search) on Monday about a European summit he attended last week.

Blair was spending the weekend at Chequers, the official rural retreat for prime ministers, when he became ill. He initially was taken to a local hospital, but then went to Hammersmith, which has a specialist coronary-care unit.

"There it was established he had an irregular heartbeat and a cardioversion was administered to regulate it," Blair's office said.

That means his heart was electrically stimulated to restore a normal rhythm.

This was the first hint of any health problems for Blair, who took power 6 years ago. He is not accompanied by a physician on his travels, his office said.

This year has been the most stressful for Blair since becoming prime minister. He has faced a storm of criticism across Britain for his decision to commit British troops to military action in Iraq earlier this year.

Blair also has appeared increasingly tired in public, often looking haggard at press conferences and other forums where he has faced constant criticism from a hostile media. He also has fended off discontent inside his Labor Party, whose left wing is unhappy about his centrist policies.

Since the war, his government has been on the defensive because coalition forces have not found evidence of weapons of mass destruction -- the heart of Blair's case for military action to oust Saddam Hussein.

Two of Blair's Cabinet ministers resigned to protest the invasion, and public opinion polls have charted growing disillusionment with his government.

There was further strain when the government became embroiled in a bitter feud with the British Broadcasting Corp. over a news report quoting an unidentified scientist as saying the government "sexed up" a dossier of evidence about Iraqi weapons.

The source, weapons adviser David Kelly, was found dead July 18 of an apparent suicide. Blair was called to give testimony at a judicial inquiry into Kelly's death.

The BBC and other television and radio channels interrupted their normal programs to report that Blair had been hospitalized.

Blair has always appeared young and vigorous and there have rarely been hints of any health problems since he took power apart from occasional colds.

In a magazine interview before his 50th birthday in May, Blair said he felt great.

"I do more exercise today than I've done since I was at school," he told Saga magazine.

"I pay more attention to looking after myself, I watch my diet a bit. But really I find it's exercise that's fantastically helpful for coping with stress."

Part of his exercise program is frequent use of a treadmill, he said.

In a Sept. 30 speech to the Labor Party conference, Blair acknowledged he had hit a "rough patch."

"I now look my age," he joked.

At international conferences, Blair is noted for appearing much younger than many of his fellow government leaders.

But the prime minister is known for taking a very direct role in all the main aspects of his government and often carries a punishing workload.

If the prime minister were temporarily incapacitated, Deputy Prime Minister John Prescott would take on his duties, Blair's office said.

If he were unable to continue in office, the governing Labor Party would have to elect a new leader, who would then become prime minister.