Tony Blair was yesterday recovering from a relatively minor procedure to correct his recurring abnormal heart beat.
He was back at home in Downing Street hours after undergoing the treatment having been expected to remain in Hammersmith hospital in west London overnight.
The smiling prime minister said: "I am absolutely fine thanks. The hospital staff, the nurses, the doctors were brilliant." The care reflected "the tremendous dedication, expertise, commitment NHS staff show every day throughout the country."
The hospital said that the procedure, thought to have lasted up to two and a half hours, "was successful in eliminating the atrial flutter. We consider the risk of recurrence of the problem to be very low".
It added that doctors expected Mr Blair to continue his "rapid and complete recovery".
The first hint that Mr Blair would quickly return to Downing Street came from Gordon Brown.
The chancellor, who was in Washington, told BBC News 24: "I think the whole country would wish him well. I know that he is now out of his operation and it's gone very successfully; and I know, too, that he is able to return to Downing Street this evening.
"I think our thoughts are with Mr Blair, and his family, for the recovery that I think everybody hopes he will have from this operation."
Mr Blair had on Thursday night described his heart flutter as "not particularly alarming, but something you should get fixed". Just after 7am yesterday, he looked relaxed, and smiled and waved, as he left Downing Street with his wife Cherie.
He arrived at the hospital, its gate flanked by police officers, 30 minutes later.
Mr Blair had said he had had the problem for a couple of months, an apparent recurrence of one that needed treatment with a different procedure, cardioversion, last October. This time he had a catheter ablation, a treatment with a high success rate.
A narrow tube called an electrode catheter, a bit like a thick electrical wire, is inserted into the body via the femoral vein near the patient's groin, and manipulated up through the interior vena cava, which carries deoxygenated blood into the right atrium, one of the chambers of the heart.
The catheter checks the electrical "circuitry" to find any abnormal pathway. When this is found, tissue is deliberately damaged by pulses from radio-frequency waves; the area may be as small as 2-3mm around the catheter tip. Sometimes more than one area has to be treated.
The patient is given a local anaesthetic to insert the catheter, and might be sedated; though conscious, he would be unlikely to suffer pain.
Huon Gray, president of the British Cardiac Society and a consultant cardiologist from Southampton, said: "The inner aspect of the heart has no pain fibres. As long as you are not hamfisted, you can do it without the patient being aware of any discomfort."
Occasionally the procedure might lead to accidental damage of the heart's natural pacemaker that could mean the patient needing an artificial one instead. "If my understanding from the very little information that is available is correct, the chances of Tony Blair needing a pacemaker are very low indeed."
Across the country, around 3,000 such treatments are given a year.
