Cardinal Keith O’Brien, formerly Britain’s most senior Catholic cleric and a man renowned for railing against homosexuality, was in a “longstanding physical relationship” with one of the men whose recent allegations brought about his downfall, it has been claimed.

According to a report in The Herald newspaper, Cardinal O’Brien confessed to the relationship after it was recently revealed there had been several complaints to the Vatican about his sexual behaviour towards priests in the 1980s.

The paper claims that the length of the relationship explains why the 75-year-old Cardinal spoke of his time as a “priest, bishop and Cardinal” when he made his brief apology earlier this month admitting that his “sexual conduct” had fallen below the standards expected of him.

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It is believed the man, who was due to speak to the newspaper before being advised otherwise by his bishop, currently lives outside Scotland.

The report will pile further pressure on the Cardinal to make a much more detailed public response to the allegations against him. Britain’s most senior serving cleric stepped down one week after accusations against him first surfaced in public from four unnamed priests who said he had approached them sexually in the 1980s.

The allegations were initially made to the Vatican’s ambassador to Britain and passed up the chain to Rome but they became public when a newspaper printed details last month.

Cardinal O’Brien initially stepped down from the church without admitting that there was any substance to the allegations. However a week later he released a brief apology which suggested there was some truth in what the priests were saying. But the statement lacked any precise detail.

According to The Herald, the man who had been in a long term relationship with the Cardinal is known to have been in regular telephone contact with him until recently and was a frequent visitor to St Benets, his official residence in Edinburgh's Morningside.