Ministers have ditched plans to put a limit on how much MPs can earn outside parliament.
The government had floated the idea in response to the Owen Paterson sleaze row last year.
Paterson was handed a 30-day Commons suspension for breaching lobbying rules, but ended up quitting as an MP after a botched attempt by Boris Johnson to redraw the Commons standards rules in an attempt to save him.
In an attempt to defuse the row, the prime minister pledged to clamp down on MPs’ outside earnings.
Deputy prime minister Dominic Raab said at the time: “You could do it in one of two ways, you could do it by the amount or you could do it by the number of hours. We’ve asked the committee on standards to work up the detail by January.”
But in the government’s submission to the committee, Number 10 chief of staff Steve Barclay and Commons leader Mark Spencer said “the imposition of fixed constraints such as time limits on the amount of time that members can spend on outside work would be impractical”.
He said: “The imposition of time limits would not necessarily serve to address recent concerns over paid advocacy and the primary duty of MPs to serve their constituents.
“It could be possible, for example, for a member to conduct work within the accepted time limits but that does not necessarily mean such work is “appropriate” even if it did not constitute ‘paid advocacy’.”
Barclay, who is also Cabinet Office minister, added: “In respect of a cap on earnings from outside work to impose such a limit could serve to prohibit activities which do not bring undue influence to bear on the political system.
“Earnings from activities such as writing books for example, would not preclude members from meeting their principal duty to their constituents.”
Thangam Debbonaire, Labour’s shadow Commons leader, said: “This is a Prime Minister who has repeatedly allowed his own MPs to put their own private business interests ahead of their constituents and it must be stopped.
“He can’t just row back on his promises to tighten up the rules on second jobs just because he is in a spot of bother with his backbenchers.”
In November, the prime minister said MPs who were prioritising outside interests over their constituents should be “investigated and appropriately punished”.
And he said the rules should be changed to ban sitting MPs from being paid political consultants or lobbyists.
“The vast majority of MP’s of all parties work tirelessly for their constituents,” he said.
“That is why it is imperative that we put beyond doubt the reputation of the House of Commons by ensuring the rules which apply to MPs are up to date, effective and appropriately rigorous.”