MPs have backed the government’s approach to curbing MPs’ outside interests, after Labour’s proposals were voted down in the Commons.

Labour leader Sir Keir Starmer used one of his party’s designated opposition day debates in the Commons to put forward a motion setting out his party’s plans for banning MPs from paid political consultancy work.

But in a bid to steal a march on the opposition, Prime Minister Boris Johnson announced he backed such a ban and put down an amendment setting out the government’s own approach.

This has now been passed, by 297 votes to zero, after Labour and other opposition MPs chose not to vote against the government amendment on Wednesday night. Labour’s own motion was earlier defeated by 282 votes to 231.

This turn of events has sparked a furious response from Labour, which accused ministers of “watering down” the party’s original motion and effectively making it non-binding.

And the move from the prime minister also risks inflaming tensions with his Tory backbenchers, amid questions and concerns at the scope of such a ban and which roles will be affected.

Labour’s motion said MPs should be banned from holding second jobs involving acting as a parliamentary strategist, adviser or consultant.

It also would have instructed the Committee on Standards to come up with plans to implement this move and to report back to the Commons by the end of January.

And it said MPs should have been able to force a debate on the contents of such a report if the government did not schedule a debate on it within 15 days of the recommendations being received.

The prime minister set out his own plans on Tuesday, at the same time as Sir Keir was holding a news conference on the issue.

Unlike Labour’s motion, it does not explicitly endorse the findings of a 2018 report on MPs’ second jobs from the independent Committee on Standards in Public Life.

The government says this report – and its recommendation of a consultancy ban – forms the “basis of a viable approach which could command the confidence of parliamentarians and the public” and believes that its recommendations “should be taken forward”.

In addition, the motion expresses support for “cross-party work”, including from the Committee on Standards, to bring forward proposals to update the MPs’ code of conduct by the end of January.

However, there is no provision for a debate in the Commons on such proposals.

And the amendment makes no mention of a proposal Mr Johnson included in a letter to Commons Speaker Sir Lindsay Hoyle to investigate and punish MPs who prioritise outside interests.

Speaking in the Commons debate, Labour’s shadow Commons leader Thangam Debbonaire accused the government of trying “to gut” the party’s motion.

She said: “At the moment I don’t see the government coming up with anything strong.

“All the government’s done is try to gut our motion, that would put in train the recommendation of the Committee on Standards in Public Life that was made three years ago that the government could have done any time.”

Commons leader Jacob Rees-Mogg said MPs’ expertise should “not be for sale”, but expressed the government’s view that it is an “historic strength” of the parliamentary system that there are MPs “with a broader range of talents and professional backgrounds”.