Commons Speaker John Bercow has been accused of behaving like an "arrogant toff" by a motorist who claims he clipped her parked car.
The row was witnessed by an Evening Standard reporter, who happened to be walking past at the time of the incident.
Nathalie Pulford, 42, was dining in London's affluent Chelsea neighbourhood when she claims she spotted Mr Bercow bump her car during a parking manoeuvre.
However, Mr Bercow denies touching the car, much less scratching it as she alleges.
Ms Pulford told the Standard: "I said to him: 'Don't you realise you absolutely bashed into my car?' - he had walloped these cars - and he said 'No I didn't. It wasn't me'.
"He would not even approach the subject. He was being really haughty, being a completely arrogant toff."
Ms Pulford said: "I could tell he bumped the car behind him because it moved. And then he bumped my car as well. I only had that car re-sprayed last year and I know every scratch on it and the scratches there now weren't there before. But that's not the point, it's the fact he wouldn't even admit responsibility and apologise whatsoever. He was just very rude about it and talked to me like I was nothing."
Mr Bercow conceded he was "not the best" driver, but maintains he kept his distance.
"She was clearly very irate, but I totally reject any suggestion the scratches on her car were inflicted by me," he told the reporter at the scene.
"Am I too arrogant to say sorry? No. I'd be happy to 'fess up, but the fact is I didn't touch her car. I'm not the best driver... yes it was a tight spot, but if I had touched her car I would have felt it."