Sir Keir Starmer has said he wants to reduce the number of people going to prison through renewed efforts to cut reoffending.

In his first press conference as prime minister, Sir Keir said too many people found themselves back in jail “relatively quickly” after being sent there.

He added that intervening to prevent young people committing knife crime would be an early priority for his new government.

But he said there would be no “overnight solution” to prison overcrowding, adding: “We’ve got too many prisoners, not enough prisons.”

It comes after he appointed a businessman as his prisons minister who has previously said only a third of prisoners should be there.

James Timpson, boss of the shoe repair chain which has a policy of recruiting ex-offenders, said in an interview with Channel 4 earlier this year that “we’re addicted to punishment”.

Labour, which won a landslide general election victory on Thursday, has promised to review sentencing after regaining office for the first time since 2010.

It has also inherited a ballooning crisis in Britain’s jails, and has already committed to keeping the previous Conservative government’s early release scheme in place to ease current levels of overcrowding.

Last week the Prison Governors’ Association, which represents 95% of prison governors in England and Wales, warned that jails were due to run out of space within days.

Tory ex-justice secretary Alex Chalk first announced plans to release prisoners early in October 2023.

Mr Chalk, who lost his seat to the Lib Dems in the general election, told MPs at the time the “prison population is greater than it has ever been” and the UK “must use prison better”.

However, he added: “We must do whatever it takes to always ensure there are always enough prison places to lock up the most dangerous offenders to keep the British public safe.”

Details of Labour’s review are yet to be unveiled, but Mr Timpson’s appointment has offered an early signal that a change of approach may be on the cards in this area.

Sir Keir has appointed him a member of the House of Lords, allowing him to take up a post as prisons minister at the Ministry of Justice.

The businessman told a Channel 4 podcast in February that prison was a “disaster” for around a third of prisoners, and another third “probably shouldn’t be there”.

He said too many people being in prison for “far too long” was an example of “evidence being ignored because there is this sentiment around punish and punish”.

“We’re addicted to sentencing, we’re addicted to punishment,” he added.

Asked about his comments at a Downing Street press conference, Sir Keir did not offer a view on whether he agreed with those estimates.

But he added: “We do need to be clear about the way in which we use prisons.

“For so many people [who] come out of prison, they’re back in prison relatively quickly afterwards.

“That is a massive problem that we have in this country, that we do need to break.”

He said his party wanted to cut knife crime in particular, and cited his plan to set up a network of “youth hubs”.

Sir Keir, a former lawyer, added: “I’ve sat in the back of I don’t know how many criminal courts and watched people processed through the system on an escalator to go into prison.

“I’ve often reflected that many of them could have been taken out of that system earlier if they’d had support”.

Steve Searby – from the Prison Officers’ Association, which represents thousands of prison workers – told BBC Breakfast the situation “has been coming for years and years”.

“I cannot see how we are getting out of this crisis,” Mr Searby said. “The situation isn’t something which is going away, you have to deal with it. There is no immediate fix.”

He added: “You need to get people who know what they are talking about around the table.”

Labour says it wants to create 20,000 prison places by enabling ministers to override local councils on planning decisions.

But it also plans to keep in place the scheme implemented by the last government under which some lower-level offenders can be released up to 70 days early.

Sir Keir said Conservative ministers had created a “mess” by failing to build enough prisons and mismanaging the prisons budget.

Defending his decision to keep the early-release scheme in place, he added: “We don’t have the prisons we need, and I can’t build a prison within 24 hours.”

The latest official figures, published on Friday, put the prison population of England and Wales at 87,453 out of a “useable operational capacity” of 88,864.

The SNP-run Scottish government, responsible for prisons in Scotland, plans to release between 500 and 550 inmates in the coming months.

It comes as Sir Keir convened the first Labour cabinet meeting in 14 years, telling his top team he expects them to hold themselves and their departments to the “highest standards of integrity and honesty”.

A Downing Street readout from the meeting said the prime minister told ministers “the whole country was looking to the government to deliver on their priorities”.

Following the cabinet, Sir Keir was grilled by journalists at his first press conference as PM.

Asked about tax hikes, Sir Keir said he would take “tough decisions” and face challenges with “raw honesty”.

The new Labour government faces tough choices on public finances, with forecasts suggesting major spending cuts.

But Thursday’s landslide victory in the General Election has given Labour “a clear mandate to govern for all four corners of the United Kingdom,” Sir Keir said as he set out plans to tour all four UK nations in the coming days.

Saturday also saw the final result of the general election, with the Lib Dems winning the Inverness, Skye and West Ross-shire constituency.

The outcome had originally been expected at about 05:00 BST on Friday, but a recount meant the results were delayed until Saturday afternoon.

Candidate Angus MacDonald gained a majority of 2,160 over the SNP’s Drew Hendry.

It means the Lib Dems have won 72 Westminster seats. Six of these are in Scotland, meaning the Lib Dems overtake the Scottish Conservatives as Scotland’s third largest party in Westminster.

Across the UK, Labour won 412 seats while the Conservatives were on 121.