Westcountry MP Ben Bradshaw attended a champagne reception in London in skin-tight cycling shorts and no trousers.
The Labour MP for Exeter raised a few eyebrows at David Miliband's farewell party by sporting a Tour de France look at a gathering of grand political figures.
Mr Bradshaw, 52, arrived by bicycle at the drinks party at West End restaurant Ozer last Tuesday, given by the former Foreign Secretary ahead of his move to the United States.
The former Culture Secretary wore cycling shorts with black socks and work shoes.
According to the Daily Mail, party-goers were "shocked", describing the outfit as "disgraceful".
But the former Culture Secretary hit back, saying: "I was dashing between events on my bike as it is the best way to get around London in a hurry.
"Obviously I was not going to be cycling in a suit in this weather. David's party was not all that formal and he is used to me turning up for things wearing them."
Guests at the function included former Chancellor Alistair Darling and ex-Home Secretaries Alan Johnson and John Reid.
Mr Miliband, who lost the Labour leadership to brother Ed, will live in New York as he heads the charity International Rescue Committee.