nn Theresa May remains "fully committed" to reforming the National Insurance

The Prime Minister has promised to listen to the concerns raised by Conservative MPs over a National Insurance hike announced in the Budget.

As she addressed the row during a press conference in Brussels, Mrs May backed the changes introduced by Philip Hammond but said there would be no vote until the autumn.

She pledged that the embattled Chancellor would speak to MPs about their concerns and publish a paper explaining the proposals before they are introduced.

A review of modern employment practices by RSA chief executive Matthew Taylor is due over the summer.

The Government paper is expected to include proposals to extend benefits such as parental leave to the self-employed.

"The Prime Minister has said that the Chancellor and his ministers will be talking to MPs and businesses over the summer," Mrs May's spokesman said. "The Prime Minister talks to MPs all the time."

Under the measure, Class 4 National Insurance contributions, which are paid by those with profits of £8,060 or more a year, will rise by 1% to 10% in 2018, with a further 1% increase in 2019.

The spokesman said the paper would spell out changes to the self-employed but also what new rights they might get.

"We are bringing forward legislation in the autumn in reference to the National Insurance announcements which were made in the Budget," he said.

Labour has claimed the Prime Minister - who with her comments in Brussels effectively put the brakes on the Chancellor's Budget proposals - had made a "partial U-turn".