Bono on the back foot over a puff of smoke

Time was when pop stars were expected to ingest large amounts of dubious substances as part of their lifestyle in the world of sex, drugs and rock 'n' roll.

Time was when pop stars were expected to ingest large amounts of dubious substances as part of their lifestyle in the world of sex, drugs and rock 'n' roll.

But U2's lead singer Bono, one of Ireland's biggest stars, has penitently apologised for smoking a single cigarette, and that in a hotel owned by his band.

He said he momentarily forgot about the Irish smoking ban.

The news of his tobacco transgression has raised many smiles in Ireland, where the ban has been almost universally hailed as a major success since it was brought in months ago.

Bono's apology is seen as demonstrating the new reality that smoking in pubs, hotels and restaurants is a thing of the past, with the Irish responding almost instantly to the argument that smoking in workplaces is wrong.

The illicit cigarette was lit up by the singer, whose real name is Paul Hewson, late at night in his band's elegant hotel, the Clarence, in the centre of Dublin. He was in the company of a Californian band, the Red Hot Chili Peppers.

He said: "It was the wee small hours. I was in the company of people from out of town who didn't know about the ban and for a moment nor did I. I was quickly reminded by the staff and a few friends. I apologised then and I apologise now."

The authorities report that 97 per cent of the premises visited by anti-smoking inspectors in the first month of the ban were found to be complying with the regulation.

The early signs are that pubs and restaurants have not, as some of them feared, lost significant business because of the ban. Around one-quarter of the population of the Irish Republic are said to be smokers. Many used the introduction of the ban as a spur to help them give up smoking. Little huddles of smokers have now become a familiar sight in the doorways of Irish bars as customers nip outside for a cigarette.

This is not the first time that Bono has landed in trouble over cigarettes. Years ago he had a nose, throat and ear operation to clear blocked sinuses, doctors reportedly warning him that smoking could worsen the condition.

His fans believe that smoking alters the Bono voice. He said: "It's dumb to smoke, and it really changed my voice, and I lost the high register, and I lost the ability to fly as a singer. I had a lot of complications with my voice anyway. The doctor told me I couldn't smoke."