The Government’s early prison release scheme has likely bought it extra capacity until autumn 2025, MPs have heard.

Prisons minister Lord Timpson and senior civil servants were pressed by the Commons Justice Committee on the impact of the scheme, which has seen two tranches of prisoners released after serving 40% of their sentence behind bars.

This was aimed at freeing up spaces in overcrowded prisons, amid warnings there could soon be no spaces left to jail newly sentenced criminals.

Lord Timpson said the stopgap scheme, known as SDS40, will likely have freed up 5,500 extra spaces within prisons over its lifetime.

But MPs also heard from Amy Rees, the chief executive of the Prison and Probation Service, that the early release scheme’s impact would likely only last until next autumn.

We think when this has come through there will be about 5,500 spaces that this will have created

She described this as a “really decent chunk of time” which ministers could use to set out longer term solutions to prison crowding, and for new jails to come into use.

Lord Timpson, formerly the chief executive of the shoemaker and retailer which shares his name, told the committee that the early release scheme was “not the first thing we wanted to do when we came into Government”.

Asked how many spaces within prisons the scheme would free up, he said the summer riots had changed estimates.

Lord Timpson told the Committee: “The projections that we were looking at, then things changed when we had the civil disobedience in August which made the situation even worse so we got to the point when we had less than 100 places in the whole of the prison estate, which to reiterate a point I have made before, is clearly not the place you want to be.”

He added: “We think when this has come through there will be about 5,500 spaces that this will have created.”

Lib Dem committee member Josh Babarinde asked how long ministers expected the extra capacity to last for.

HMPPS chief Ms Rees replied: “It is certainly fair to say that that has bought us a really decent chunk of time. Five thousand five hundred is what it is expected to yield in steady state; 4,500 is about what we expect incoming demand to be.”

She added the opening of HMP Millsike in York in 2025 would help grow prison capacity, but claimed the events of the summer was among the factors which made it difficult to predict how long the space would last.

Ms Rees insisted ministers have “definitely got enough time” to conclude the independent sentencing review led by former MP David Gauke before setting out longer term reforms, and that other interim measures would help “get us well through the autumn”.

“We are not now staring down the barrel of facing an immediate crisis like we were in the summer,” Ms Rees added.

Eastbourne MP Mr Babarinde asked: “Then next autumn is the time by which you expect, all other things being equal, this reprieve to last for until prisons reach capacity?”

“We may get further than the autumn,” the senior civil servant replied, adding that winter often led to a “Christmas dip” in prison capacity which may extend the period extra capacity is available.