Hate preacher Omar Bakri Mohammed may undergo heart surgery in an NHS hospital if he returns to the UK.
Bakri, who says he has a congenital heart problem, has already missed several appointments or had them postponed, friends said, but another one is likely to be scheduled before the end of the year.
The so-called “Tottenham Ayatollah” is currently in Lebanon but says he plans to return to the UK in a month’s time.
That would allow him to have a free operation which would otherwise cost thousands of pounds privately.
Bakri’s health problem is understood to involve the narrowing of arteries in his heart and the likeliest operation is an angioplasty.
More than 20,000 of the operations are carried out by doctors in the UK every year.
His condition is believed to be exacerbated by his weight.
Friends say that, because he is missing a bone in his ankle, he is unable to exercise and that has contributed to the narrowing of his coronary arteries.
Earlier this year the father-of-seven, who uses a walking stick, took delivery of a £30,000 Ford Galaxy people carrier paid for under the Motability scheme.
He is estimated to have received several hundred thousand pounds in benefits during his two decades in the UK.
It is not clear which hospital Bakri would have his treatment at and hospitals refused to discuss confidential patient details.
But Anjem Choudary, another leading figure in the al-Muhajiroun movement, said: “He had an appointment for a heart operation at some point. I’m not sure exactly when.
“He had appointments before but he missed them – he doesn’t like to take medicine, he likes to recover naturally.
“He has a congenital problem he has had the whole of his life. It’s a problem with his arteries but I’m not a doctor so I don’t know exactly.”
Bakri, who had his mobile phone turned off today, sparked outrage last week by saying he would not inform police if he knew Muslim extremists were planning a bomb attack in Britain.
He left for Beirut amid suggestions that he could be tried for treason but the Government has since made clear there is no prospect of that.
Deputy Prime Minister John Prescott admitted there was nothing to stop the firebrand cleric coming and going at the moment from the UK.
But a review of the Home Secretary’s powers to exclude people who promote terrorism could be complete by the time Bakri heads home, allowing him to be barred.
Tory leader Michael Howard argued that present powers were already sufficient to keep Bakri out and he called on the Government to use those powers “without delay”.
“The Home Secretary has the power to exclude from this country people whose presence here is not conducive to the public good,” he said.