David Cameron blocked tighter controls on lobbyists that would have covered his work for the collapsed bank Greensill, Labour has claimed.
The rules, proposed as amendments to the 2014 Lobbying Act, would have required Mr Cameron to register are a lobbyist – but were blocked by Tory peers.
Labour said it was "disgraceful" that that the former prime minister had ordered MPs to vote against controls whose absence he was now benefiting from.
The prime minister has been advising the bank Greensill Capital since 2018.
His work reportedly included lobbying chancellor Rishi Sunak by text message in a bid to get the institution access to a state-backed Covid loan scheme.
There is no suggestion that Mr Cameron has broken any rules.
As PM Mr Cameron's government introduced a statutory register of lobbyists, but its narrow terms mean it does not appear to apply to him.
Amendments to the Lobbying Act 2014 proposed by Labour would have required many in-house lobbyists to register in the same way as external consultants do.
But the amendments were defeated by 218 votes to 185 in the House of Lords after resistance from Tory peers.
Rachel Reeves, the shadow cabinet office minister said "Conservative cronyism" had weakened the British economy.
“It is shocking that a former Conservative Prime Minister not only boasted about how much money he would make from Greensill Capital, but also gave them an open door to government, starting with profiting off our NHS and ending with steelworkers’ jobs at risk," she said.
“Voting down the very measures that could have stopped Cameron’s poor and hypocritical conduct in the first place is disgraceful. It’s the latest example of how Conservative cronyism has weakened our economy, costing jobs and taxpayer money.”
Mr Cameron has not commented on the affair.
It comes as the opposition party called for the Committee on Standards in Public Life to examine the role of the bank’s founder in Mr Cameron’s coalition government.
The Sunday Times at the weekend claimed that Lex Greensill was given "privileged access" to government departments under the Tory leader.
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