Like Boris Johnson, Keir Starmer has been doing the rounds on UK media ahead of the local elections this Thursday.
The BBC’s Martha Kearney put it to Mr Starmer that “what the government has also done is it’s changed the threshold on [national insurance contributions] so that people who earn less than £35,000 will actually see those national insurance bills drop – that’s according to research from the Institute for Fiscal Studies.”
The Labour leader replied: “Well, most families will be much worse off.”
FactCheck takes a look.
National insurance contributions (NICs) are a tax that workers pay on their earnings over a certain level and that employers pay based on the earnings of the people they employ.
How much you pay in NICs depends on two key elements: the rate of NICs, and the threshold at which it kicks in.
The NICs rate rose by 1.25 percentage points on 6 April this year. That means the standard NICs rate for employees has gone from 12 per cent to 13.25 per cent.
At first glance, that’s a tax rise.
But the government is also raising the threshold at which employed and self-employed workers start paying NICs. That change – which takes effect from July – means workers can earn £12,570 a year before they have to start paying NICs, considerably more than the previous threshold (£9,880).
Taking account of the threshold change means that “those earning less than around £35,000 will see a fall in their overall NICs bill in 2022-23 relative to 2021-22”, according to the independent think tank, the Institute for Fiscal Studies (IFS).
So what about Sir Keir’s claim that “most families will be much worse off”?
It’s possible that he was talking more generally about the overall cost of Conservative tax policies beyond NICs.
But this section of the interview was on the NICs issue specifically – so we’d expect most listeners to assume that that’s what this claim refers to.
And whether or not it’s correct depends on what time period we’re talking about.
Between April and July this year, workers are paying a higher rate of NICs (tax rise) without the benefit of the threshold increase (effective tax cut). So it’s fair to say that for those three months, most workers will pay more in NICs than before.
But across the whole financial year – April 2022 to April 2023 – the majority of workers will see their NICs bill fall, thanks to the rise in the threshold.
Stuart Adam, senior economist at the IFS, told FactCheck: “It is not the case that in this tax year as a whole most people will pay more NICs.”
“Take the year starting from April  onwards,” he added, “most employees and self-employed people will be paying less NICs, not more.”
In a conversation about the government’s changes to national insurance, Keir Starmer said that “most families will be much worse off.”
That may be true for the period April 2022 to July 2022. For those three months, most workers are paying a higher rate of national insurance (a tax rise) and have yet to benefit from an increase to the national insurance threshold that’s slated for the summer (which will be an effective tax cut).
But the independent Institute for Fiscal Studies tells FactCheck that across the whole financial year (April 2022 to April 2023), the majority of workers will pay less national insurance than they did last year.