The Chancellor said the move would raise money to boost social care and reduce the gap in contributions between the employed and the self-employed, saying it could “no longer be justified”.
Self-employed workers paying the main rate of class 4 National Insurance contributions would see an increase by 1 per cent to 10 per cent in April 2018.
An 11 per cent increase in April 2019 is set to follow, altogether raising £145million a year by 2021/22 at an average cost of 60p a week to those affected.
Speaking to Nick Robinson on BBC Radio 4’s Today programme, Mr Hammond said the UK was facing “new challenges” that it needed to “rise to”.
Philip Hammond said his budget ensured the UK was match fit for Brexit
Much of our spending is also ringfenced and committed and we are navigating within those confines to try and prepare Britain for Brexit, to make sure we’re match-fit for Brexit
“I’m doing that within a very constrained environment where most taxes cannot be raised,” he added.
“Much of our spending is also ringfenced and committed and we are navigating within those confines to try and prepare Britain for Brexit, to make sure we’re match-fit for Brexit, to invest in Britain’s future and at the same time to provide much-needed resource for our public services.”
Robinson probed the Chancellor and asked if his budget was “white van man” and “white van woman” having to “pay the price for voting Brexit”.
Mr Hammond dismissed the claim and said: “The key circumstance that has changed in respect of the self-employed, is that they now have access to the full state pension on the same basis as employees, that is worth £1,800 a year for a self-employed person.
Find out what the BUDGET means for YOU Wed, March 8, 2017
Budget 2017: Philip Hammond hailed Britain’s booming Brexit economy today as he delivered his first Budget of the year
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Mr Hammond says he is 'building the foundations of a stronger, fairer, more global Britain'
Mr Hammond said he had to adapt his budget because of "changing circumstances"
“And it means that the gap in National Insurance contributions between the employed and the self-employed can no longer be justified.”
He added: “We’ve introduced this measure because we need to raise revenue in this budget in order to fund social care.”
Robinson then grilled the Chancellor on whether he “needed” to raise money by “getting the self-employed to pay for it”.
“We have to pay for these things somehow and this is a difficult challenge,” Mr Hammond insisted.
The host responded by telling the Chancellor to “tax companies or the rich” but Mr Hammond maintained: “We’re already doing all of those things, no Conservative likes to raise taxes.”