A barrister accused of exposing himself to bridesmaids at a wedding reception before beating up a guest has told a court he was acting in self-defence.
Best man Christopher Dunn, 40, of Morley, Leeds, allegedly flashed at a group of women before being dragged away by guest David Baird-Dean.
The barrister denies later causing Mr Baird-Dean grievous bodily harm with intent at the wedding in Pately Bridge.
He also denies a charge of inflicting grievous bodily harm.
Giving evidence at his trial at Preston Crown Court on Monday, the lawyer said he had been "frightened" at being dragged across the lawn by Mr Baird-Dean, 48, during the reception at the Harefield Hall Hotel.
He said Mr Baird-Dean later attacked him, throwing punches at his head.
He then struck back and hit the mechanic as hard as he could in an effort to knock him out.
The court heard Mr Baird-Dean suffered such severe injuries that surgeons had to use metal plates and screws to reattach his upper jaw and both eye sockets to his skull.
Mr Dunn told the court he had been "terrified" as a "relentless" Mr Baird-Dean attacked him.
He said: "I was frightened he would knock me out with a lucky punch and then really go to town . . . I couldn't let that happen.
"I hit him as hard as I could. I was aiming for his chin. It was a very hard punch.
"I thought it would have knocked him spark out. I threw a flurry of punches."
Mr Baird-Dean fell to his knees and Mr Dunn stopped the fight when he realised the extent of the mechanic's injuries.
Under cross-examination, Mr Dunn denied using excessive force.
He said: "I never sat astride David and punched him unconscious on the floor."
The trial continues.