The UK chancellor is facing accusations that he has broken repeated promises not to increase taxes, including national insurance contributions.
Those pledges were a key part of then prime minister David Cameron’s pitch to attract working-class voters, as he sought to portray the Tories as “the party of working people”.
Conservative backbench MPs began to signal their anger shortly after the chancellor delivered his first Budget.
Anne-Marie Trevelyan said she was worried about the impact of the national insurance changes on the self-employed. “They are risk-takers . . . next generation business leaders, [with] no statutory sick leave or holiday pay,” she tweeted.
Andrew Murrison said he had “concerns” about the impact on “white van man and woman”, of whom he said the Conservative party “has always and I hope always will” support.
“I hope very much we can have some reassurance from the Treasury that plumbers and electricians and plasterers and people of that sort are not going to be disadvantaged,” he said.
Jacob Rees-Mogg said he could “see the logic” in Mr Hammond’s proposal because “there is an unfairness between self-employment and employment”. But, he said: “I’m not sure that making a minor change at the edge is the right way of going about changing the relationship.”
After a series of Tory MPs raised their concerns publicly during the Commons debate, Mr Hammond faced backbenchers at a private meeting in Westminster on Wednesday evening.
He received a warm but muted reception at the event during which two senior figures in the party expressed doubts about the policy, according to people with knowledge of the situation.
But the chancellor was adamant that his Budget did not break the party’s manifesto commitments, others who were present said.
One Tory loyalist claimed that Mr Hammond had put in a solid Budget performance but acknowledged that the tax issue was “a chink in the armour” for the party.
One backbencher who did not want to be named said he was “pissed off” about the policy, which he said was a “poor decision”. As for the political reaction within his party, he said: “It’s not good.”
Another backbencher, when asked how he thought the Budget went, texted an embarrassed emoticon in response.
But some loyalists backed the chancellor.
Bernard Jenkin, a senior backbencher, said the Budget was solid, tough, realistic and strategic, although he also acknowledged that there would be “plenty of people complaining about taxes and continued spending restraint”.
Alan Mak, a backbencher, acknowledged that the self-employed might be concerned about the measure but argued that it could be offset by low corporation tax and the income tax threshold rise.
Mr Hammond’s predecessor George Osborne offered a gesture of support, saying: “Well done, Phil. Sound money and fiscal responsibility are the only secure foundations of a fair and strong economy.”
There were some comparisons to Mr Osborne’s “omnishambles” Budget in 2012.
“It’s not on that scale,” one Tory MP responded. “But it’s not great headlines.”