The Bishop of Southwark has said it would have been "entirely out of character" if he had been drunk after a drinks reception.
The Right Reverend Tom Butler said he still had amnesia and was having "extensive" medical tests.
He remembers nothing after leaving the Irish embassy and arriving home, but still believes he was mugged.
He said: "I would not be able to do my job if I got drunk," insisting he had no intention of resigning.
"I have been going to receptions for 20 years," he told BBC Radio 4's Today programme in his first broadcast interview.
"Normally, at a reception, I will have a glass or two of wine. I'm very careful.
"I don't get drunk frequently. I would not be able to do my job if I got drunk. I certainly don't think it's a resigning matter."
The bishop suffered head injuries and lost his mobile phone and briefcase on his way home from the reception in Hyde Park Corner.
"My injuries are compatible with being mugged," he said.
However, police have said they were treating the incident not as a mugging but as a case of missing property.
Eye-witness Paul Sumpter claimed the bishop fell on the pavement, hitting his head, after trying to get into the property developer's car.
A few days later, Mr Sumpter's wife allegedly discovered Mr Butler's briefcase in the car.
The bishop said he had used public transport to make his way home in Streatham, south London, on the evening of 5 December.
"I defy anyone who had too much to drink to make that journey," he said.
Bishop Tom denied the allegations surrounding the incident and said he would undergo further medical tests.
"It's very worrying, I still have amnesia," he said.
"We're going though the whole gamut because we're worried. I want to get to the bottom of it."