We already have a cyclist mayor of London in Boris Johnson, and a potential cycling Prime Minster in David Cameron. Now, according to the BBC, one of the candidates to replace Michael Martin as Speaker of the House of Commons is Sir George Young, the 'bicycling baronet' who has a history of positive contributions to cycling legislation.
There are some backbench cycling MPs (such as Emily Thornberry) too. But we'd have to go some way to return to the kind of cycling levels among members of the House at the turn of the 19th century. A column in the Pall Mall Gazette of Saturday 13 August 1898 had this to say about the Parliamentary recess:
Parliament is away, and, to a large extent, awheel. In popularity with members of Parliament the bicycle can give many points to the motor car and yet beat that mechanical atrocity hollow. Nor is the passion for wheeling confined to any section or any party in the House. The Lord Advocate of Scotland is enthusiast enough to essay to travel northwards and homewards from Westminster by this agreeable means, though we doubt whether he will complete the journey in this way; Mr. William Field, whose robust brogue is the delight of the House of Commons, is one of the latest victims of the prevailing epidemic, while Mr. Healy's partiality for the cycle led him to defend the privileges of its riders with quite remarkable vigour in the House the other day. Sir John Gorst's lurid machine, coloured a Post Office red, is an object of daily wonderment in the Session, as he wheels gently down Victoria-street. Mr. Stuart Worley is a constant and careful rider; and Sir Howard Vincent is greeted with a benevolent grin by hundreds of his blue-coated former subordinates as he careers about the West End. The officials of the House, too, have quite taken to the exercise, and one of them, Mr. Archibald Milman, is at this moment covered with honourable bruises sustained in the too eager pursuit of this kind of pleasure. But the cycle is no respecter of the persons of its riders.
Thanks, as ever, to the comprehensive, searchable British Library website of digitised newspapers (it's paid-for with some free content if accessed outside the library, but all free inside).