“We can’t shy away from the fact that Britain is facing a housing crisis. And yet, with new council housing at a record low, the Tories are announcing a cut in the house-building budget. We’ll rebuild Britain properly, starting with 1 million new genuinely affordable homes.”

That’s what Jeremy Corbyn tweeted on Wednesday after Theresa May’s speech at the National Housing Federation conference.

Claim 1: ‘New council housing at a record low’

This is correct. According to the latest figures from the Ministry of Housing, Communities and Local Government, just 5,900 new “social rent dwellings” were added to the housing stock in England in 2016-17.

That’s the lowest annual increase since comparable records began in 1992-93. It’s well below the average growth rate over the period — just under 30,000 new council homes a year.

Claim 2: ‘The Tories are announcing a cut in the house-building budget’

This is wrong. Theresa May announced more funding for house-building this week, not less.

Here’s what the Institute for Fiscal Studies told FactCheck that Wednesday’s announcement was “an additional £2 billion of funding spread over ten years (£200 million per year on average) which is about a 20 per cent annual increase. That takes the capital grant budget including this new money from 2018-19 onwards to ~£1.2 billion per year (although it would be lower in real terms).

[Update for clarity: the phrase “although it would be lower in real terms” means that when we account for inflation, the total spending on housing wouldn’t be quite as high as £1.2 billion. It does not mean that the announcement Jeremy Corbyn was referring to constitutes a cut. Theresa May’s announcement is still an increase compared to what had been planned.]

The IFS spokesperson continued:

“Therefore, as far as I can tell the PM did not announce a cut [on Wednesday], she announced additional funding. However, it was a small compared to how much lower grant funding is now than it was in 2008, before it was cut by the coalition government.”

There is one complicating factor here, which the IFS helped to explain.

In the first three years of coalition government, capital grant funding — which is one of the main ways local authorities fund social housing — was slashed by 63 per cent in real terms.

But since then, the government has launched two big waves of funding for social housing — the Affordable Homes Programme, which ran between 2015 and 2018, and the Affordable Homes and Shared Ownership Programme, which began in 2016 and will wind up in 2021.

These funding programmes overlapped for two years, which means that in 2016-17 and 2017-18, there was a spike in spending compared to previous years of the Conservative government. Funding has now dropped back down after the Affordable Homes Programme came to an end.

It’s true that capital grant spending on council houses is lower than it was before 2010, but the Prime Minister’s announcement this week is not cut in its own right. In fact, it will see housing funding increase above the level that was planned.

We asked Labour why Mr Corbyn claimed the announcement was a cut. They haven’t got back to us, but we’ll update this article if they do.