Boris Johnson promises to raise National Insurance threshold

The Conservatives would  hand millions of workers a tax cut by increasing the National Insurance threshold, Boris Johnson has announced.

Taking question on the campaign trail, the Prime Minister said the Tories wanted to increase the salary at which NI contributions kick in to £12,000 a year.

His announcement, while meeting workers at a factory in Teesside, sent campaign staff into a panic as it was supposed to remain under wraps until the party's election manifesto is unveiled on Sunday.

Asked by a worker whether his plans for lower taxes were for "people like you or people like us", Johnson replied: “I mean low tax for...working people. 

"If we look at what we’re doing, and what I’ve said in the last few days, we’re going to be cutting National Insurance up to £12,000,  we’re going to be making sure that we cut business rates for small businesses. 

"We are cutting tax for working people."

The National Insurance threshold is currently £8,628, with the Tory manifesto expected to pledge an increase to £9,500 initially, before taking it to £12,500 over the next 10 years.

According to Paul Johnson of the Institute for Fiscal Studies, every increase of £1,000 in the threshold costs the Treasury £3bn.

Shadow Chancellor John McDonnell said: "Even after 10 years of cruel cuts and despite creaking public services, the Tories still think the answer to the challenges of our time is a tax cut of £1.64 a week, with those on Universal Credit getting about 60p.

"Meanwhile independent experts have said this will cost up to £11 billion so everyone who relies on public services and social security will be wondering whether they will be paying the price.

"The Tories are stuck in the 1980s while a Labour government will tackle head-on the climate and human emergencies of our time."