With all three of the main parties whipping their MPs in favour of Lords reform, the result of tonight's vote (the programme motion having been withdrawn) was never in doubt. MPs voted overwhelmingly by 462-124 to give the bill a second reading.

But the real story is the size of the Conservative revolt. With 91 Tory MPs voting against the bill, it was the largest rebellion since the formation of the coalition, beating the previous record of 82 set by the EU rebels last year. The rebels were just four short of matching the largest Conservative rebellion of the post-war era over the Major government's post-Dunblane firearms legislation. Conor Burns, PPS to Northern Ireland Secretary Owen Paterson, resigned from the government in protest earlier today, and Angie Bray, PPS to Cabinet Office minister Francis Maude, was sacked immediately after the vote. As ConservativeHome notes, if one takes into account the number of Tory abstentions, more than half of all the party's backbenchers defied the whip and refused to vote for the bill.

By withdrawing the programme motion at the eleventh hour, Cameron avoided the ignominy of an outright Commons defeat. But his authority has been badly dented by tonight's vote. As in the case of the EU referendum vote, the PM was forced to rely on Labour votes to carry the day.

As I wrote earlier, the fate of Lords reform now lies in Labour's hands. If Ed Miliband agrees to the use of closure motions to prevent filibustering by the rebels, the bill could yet make it through the Commons. The key question is what the coalition will have to offer Labour in return for its backing. One possibility, as I suggested in my last post, is that Cameron and Clegg will agree to a referendum, a proposal that Labour endorsed in its 2010 manifesto and that a number of Tory rebels also support.