Actually, I can understand that. One in his position does work at home and on the weekends (reads secret white papers, etc.). Not only are the papers too bulky but they are a security risk on the bicycle.

An Iranian agent searching for Bush's plans against his country runs into Cameron, strong arms him and away he goes with the weekend's reading.

Still, a good example (and good exercise),

Alan

He received so much adverse comment when he was first caught with his chauffeur following on behind that he no longer does that. He has fitted a large pannier with locks on it. How confidential are the papers he carries in it, I don't know. Here is one of the pictures that were published in the Daily Mirror showing him shooting a red light approaching the Houses of Parliament with Big Ben on the left.

David Cameron on bike