British Prime Minister Tony Blair reportedly underwent a procedure Friday to correct an irregular heartbeat a condition that first surfaced a year ago and was recovering.

Aides refused to say whether the 2 1/2-hour procedure, called a catheter ablation, took place. But Sky News TV, quoting anonymous sources, said Blair underwent what he had called a “routine operation” before noon.

Blair, 51, looked relaxed as he was driven away from his Downing Street residence, accompanied by his wife, Cherie, in an official car at about 7:05 a.m. He told reporters he felt fine.

The medical procedure involved a local anesthetic, Blair said.

“It’s a sort of fluttering. It doesn’t stop you working, and indeed I’ve been working the last couple of months since it happened,” Blair said Thursday night, just hours after appearing onstage for the closing ceremony of his Labour Party’s annual convention. “I’m going to go in and have this routine operation.”

Blair’s condition is called supraventricular tachycardia. The British Heart Foundation said the condition, which may be accompanied by shortness of breath, dizziness or fainting, can be distressing for the patient but is not considered serious.

“Many people experience them at some time, even if they have no evidence of heart disease,” spokeswoman Cathy Ross said.

Blair has had his toughest two years as prime minister, facing intense opposition even from his own party to his support for the U.S.-led war in Iraq. The war overshadowed this week’s convention, and Blair is battling to unite his party as it aims to seek a third term in power.

His announcement Thursday that he would serve a full third term followed months of speculation that he intended to step down midway through it and pass the baton to his powerful Treasury chief, Gordon Brown.

“If I’m elected I would serve a third term,” Blair said. “I do not want to serve a fourth term, I don’t think the British people want a prime minister to go on that long but I think it’s sensible to make plain my intention now.”

He took office in 1997, and his Labour Party also won elections in 2001.

Blair’s condition is caused by rapid electrical activity in the upper parts of the heart and results in a sometimes irregular, rapid heartbeat.

The procedure involves inserting a catheter through the groin and up to the heart, where radio-frequency energy is used to kill off the cells conducting the extra impulses.

Blair’s office at No. 10 Downing St. said the prime minister will spend Friday night in the hospital and rest over the weekend before returning to “normal duties” Monday. He will go ahead with a scheduled visit to Africa on Tuesday, the office said.

Blair said his doctor assured him the heart condition was not connected to anything more serious.

“I feel fine. I feel great. What happens every so often is that you get a flutter. ... Apparently there is a procedure that is very easy to do and fixes it,” he said.

Blair’s condition first came to public attention a year ago when he was treated at a London hospital for a rapid, irregular heartbeat. An electric jolt was used to return his heart rhythm to normal.

On that occasion, he returned to work a day later, defying doctors’ orders to take 24 hours of rest.

A month later, in November 2003, his aides were quick to play down another health scare when Blair called doctors to his official residence. His office said he was suffering from a stomach ache that passed quickly with no treatment given by the two doctors examining him.

Blair’s procedure comes less than a month after his 58-year-old former colleague in the White House, Bill Clinton, underwent quadruple bypass surgery in New York.

Blair has seen his popularity slump since the Iraq war and the U.S.-led coalition’s failure to find evidence supporting his prewar contention that Saddam Hussein possessed stockpiles of weapons of mass destruction.

During a speech to his party’s conference Tuesday, Blair acknowledged British intelligence on the weapons threat posed by Iraq was wrong, but he pointedly refused to apologize for toppling Saddam, insisting the world was safer with him in prison.

But the usually bullish and defiant prime minister was contrite.

“I’m like any other human being, as fallible and as capable of being wrong,” he said, insisting that he went to war to protect Britain’s security.

Deputy Prime Minister John Prescott stood in for Blair while he underwent the operation and said Blair was not concerned about the hospital visit.

“He is not worried at all. He is very happy,” Prescott told ITV News.

A spokeswoman for the prime minister also confirmed Friday that the Blairs had bought a house in London’s exclusive Connaught Square, paying $6.5 million for the property. They purchased it “for their future,” and none of the Blair family planned to move in immediately, she said.