Boris Johnson has promised to raise the National Insurance threshold from £8,600 to £12,000.
A worker at a factory on the River Tees asked him: “”You said low tax, do you mean low tax for people like you or low tax for people like us?”
And he told them: “We are cutting tax for working people.”
It means anyone earning under £12,500 on Pay As You Earn (through an employer) will be taken out of paying National Insurance altogether in five years.
Everyone earning more than that could see a tax cut of around £460 a year by the end of that time.
He said it would be raised to £9,500 next year, with the “ultimate ambition” to increase it to £12,000 if they win the December 12 election.
That will see a tax cut of £100 next year for everyone paying them.
The IFS said it will cost £3billion a year for every £1000 that the threshold goes up – a total of £11billion in future.
But it will take 2.4million low-paid workers out of paying NI contributions altogether.
The Tory manifesto is expected to come out within the next week, outlining the party’s full plans for the country.
The cut would help the lowest paid workers the most, who have already benefited from the Tories’ raising of the limit they start paying income tax over the last five years.
Business Secretary Andrea Leadsom dropped a huge hint that the move was coming last month, saying: “A Conservative government will always be a tax-cutting government.
“We will set out more in the manifesto about our ambition for income taxes.”