Boris Johnson suffered a significant mutiny in parliament last week – with some striking names among the rebels

Boris Johnson has a large majority in parliament and yet lost a vote on Tuesday by a margin of five. It didn’t attract as much attention as it deserved because it was formally a free vote – that is, Conservative MPs were allowed to vote as they thought best, rather than being required to follow their whips’ instructions.

Neither side tried very hard to get their MPs to vote, and large numbers didn’t vote at all, but Tory MPs were told by their whips that they were expected to vote against a Labour amendment tabled by Chris Bryant, and it is significant that 45 of them felt strongly enough to vote for it.

The question was whether the new scheme for handling complaints against MPs of bullying or harassment should be completely independent. The plan is to set up an independent panel to hear complaints, but Bryant’s amendment sought to close a loophole that would mean MPs could debate complaints against them in the House of Commons.

The 45 Tory rebels who ensured the government’s defeat included some striking names. Theresa May was the best known, leading a phalanx of ex-ministers of the old regime, many of whom have a proud record of taking allegations of bullying and abuse seriously. Penny Mordaunt, the paymaster general, was the only minister to vote for the amendment: a Brexiteer, she was sacked as defence secretary by Johnson last year but brought back into government in the February reshuffle (in which Sajid Javid resigned). In Yes, Minister her vote would be called a “brave” decision.

Then there was a group of parliamentary traditionalists, such as Sir Bernard Jenkin, Philip Hollobone and Mark Garnier, keen to show that their reverence for the old ways does not excuse unacceptable behaviour.

But the most significant group of rebels were the new MPs who were elected only seven months ago: 22 of them voted against the government, only two of whom had done so before. That is not how new MPs normally behave. All governments expect trouble from former ministers and others who have given up hope of ministerial office, but new MPs can usually be persuaded to stay in line by the prospect of promotion.

MPs’ rebelliousness has been growing over the decades. Even Tony Blair had problems. Within seven months of his election with a majority of 179, he suffered a rebellion by 46 Labour MPs over a cut to lone-parent benefit. But he didn’t actually lose a vote until after his third election win.

Johnson must be worried that his new troops are not as biddable as they might have been in the past. Professor Philip Cowley’s research into MPs’ rebellions finds that if MPs vote against the government once, they are more likely to do it again. A majority of 80 doesn’t look quite so impressive now.

Yours,

John Rentoul

Chief political commentator