Doctors now investigate if medical problem could explain cleric's behaviour

Doctors are investigating whether a minor stroke may to be blame for the erratic behaviour of the Bishop of Southwark, who was found on his doorstep with head wounds after a night out.

The Right Rev Tom Butler has come under increasing pressure to explain the bizarre events that occurred when he left a Christmas drinks reception at the Irish embassy earlier this month.

The Radio 4 "Thought for the Day" contributor told his 300-strong congregation that he was unable to wear his mitre after being mugged the night before. It was later claimed that the bishop had left his belongings in the back of a car after getting drunk.

Now it has emerged that tests have been carried out to establish if the bishop suffered a form of "brain attack" or brain bleed caused by a small clot or artery blockage. This could explain why Dr Butler, 66, has no memory of what happened on the night of 5 December, including how he received a cut to the back of his head or came to lose some of his possessions.

A senior churchman said: "We are thinking it is possible that Tom had a minor stroke. That would explain his behaviour."

Scotland Yard said the bishop, who had suffered head injuries, did report his belongings missing to Southwark Police, but no allegation of robbery was made. Some Christian groups have called for the bishop to resign after his mysterious night out, which began with a reception at the Irish embassy.

A guest said: "He was clearly drunk. We were introduced as he left, and he asked me, 'What's the solution in Iraq?', while grabbing my arm in a vice-like grip. I told him that there wasn't a simple one, but he asked the same question again and continued to hang on to my arm for about five or six minutes."

A young couple also said that they found a man in the back of their Mercedes car on the same night.

Paul Sumpterand his wife Nicola were inside the Suchard pub on Crucifix Lane in Southwark when their car alarm went off. Mrs Sumpter said that her husband had pulled the intruder out of the back of the car and that the man fell over, hitting his head.

Asked what he was doing, the man said: "I'm the Bishop of Southwark. It's what I do", and staggered off.

The bishop's office refused to discuss his medical condition but said: "The bishop really does not remember. When the bishop got home, he informed the police and he sought medical advice."

Dr Butler is expected to give a talk in the popular "Thought for the Day" strand on Radio 4's Today programme on Tuesday morning.