“Under the Labour party, 1.4 million people spent most of the last decade trapped on out-of-work benefits.”

That was Theresa May’s claim at Prime Minister’s Questions this week.

The Department for Work Pensions (DWP) showed us the source of this claim, which supports Mrs May’s assertion that in 2009, there were 1.4 million people who had been on out-of-work benefits for at least nine years.

But the same document also shows that the category “out-of-work benefits” includes people claiming incapacity benefit, severe disablement allowance and employment and support allowance.

In other words, some of the 1.4 million benefit claimants were not in a position to seek work because they were too unwell or disabled. We’ve asked DWP to break down the 1.4 million figure further. We’ll update this article if they get back to us.

However, separate data from the DWP sheds some light on the proportions of people claiming out-of-work benefits. On average, 57 per cent of claimants between 1999 and 2009 were doing so because of disability or illness.

This suggests that the majority of the 1.4 million people Theresa May is referring to would never have been in a position to work.

The number of people on jobseeker’s allowance – which might be a more accurate measure of economic success than the number of people who are disabled – actually fell between 1999 and 2008.

It was only in the very end of the decade (when the financial crisis hit the UK) that the number of jobseekers rose significantly.

FactCheck verdict

Mrs May is technically right that 1.4 million people spent most of the 2000s on out of work benefits. But what she didn’t make clear is that this includes people on disability or illness benefits.

If Mrs May is trying to use the headline figure to criticise Labour’s economic record, this data does her no favours.