Britain's most senior Roman Catholic Cardinal Keith O'Brien has resigned amid "inappropriate behaviour" allegations.

According to the Scottish Catholic Church, the Vatican accepted O'Brien's resignation from his role as the Archbishop of St Andrews and Edinburgh in November. That resignation has now taken affect.

He was originally due to retire next month at the age of 75.

O'Brien's resignation follows allegations that he had been reported to the Vatican by three priests and a former priest over allegations of inappropriate behaviour. He denies the claims.

A spokesman for the 74-year-old cardinal was taking legal advice.

In a statement following his resignation, O'Brien offered his apologies "to all whom I have offended".

O'Brien said he would not attend the papal conclave to decide on the next pope. He was due to be the only Briton who would have a say in who takes over from Pope Benedict XVI when he stands down on 28 February.

Indifferent health

O'Brien said: "Approaching the age of 75 and at times in indifferent health, I tendered my resignation as Archbishop of Saint Andrews and Edinburgh to Pope Benedict XVI some months ago.

"I was happy to know that he accepted my resignation 'nunc pro tunc' - (now - but to take effect later) on 13 November 2012. The Holy Father has now decided that my resignation will take effect today, 25 February, 2013, and that he will appoint an apostolic administrator to govern the archdiocese in my place until my successor as archbishop is appointed.

"In the meantime I will give every assistance to the apostolic administrator and to our new archbishop, once he is appointed, as I prepare to move into retirement.

"I have valued the opportunity of serving the people of Scotland and overseas in various ways since becoming a priest. Looking back over my years of ministry, for any good I have been able to do, I thank God. For any failures, I apologise to all whom I have offended.

"I thank Pope Benedict XVI for his kindness and courtesy to me.

"I will not join them for this conclave in person. I do not wish media attention in Rome to be focused on me - but rather on Pope Benedict XVI and on his successor."