Tech agency Blanc & Otus MD Zena Martin and account director Kirsten Ackroyd left their tops at home last Saturday night to raise £1,400.
The exhibitionists were also chuffed by the fact that after six hours and 37 minutes, they had beaten the event's headline celebrity, model Nell McAndrew, to the finishing line. Although to be fair to Nell, she was carrying quite a weight in her costume.
Despite, or perhaps because of, the presence of 'boys hanging out of cars and honking their horns in amazement at all those women with their kit off', Martin says she would 'definitely do it again next year'.
Other celebrities to brave the chill included Koo Stark, Victoria Wood, Alex Best and Anthea Turner.