Dominic Raab has announced the creation of 4,000 new prison places in England and Wales, as the government plans for an increase of almost 25% that could take the prison population to an all-time high.

There were 79,765 prisoners in England and Wales in the week ending 11 February, according to Ministry of Justice figures, while the maximum capacity in the system was 81,368.

The latest announcement of 4,000 new places, which will include extending or refurbishing 16 prisons, is part of a plan to provide 20,000 “innovative” new prison places by the mid-2020s.

If all these were taken up, it would push the prison population to its highest ever level, above 100,000. The previous peak was 88,000 in November 2011.

Prisons being extended or refurbished as part of the new announcement include Birmingham, Liverpool and Norwich. Projects have already been completed at four other prisons, including Feltham and Aylesbury.

The Ministry of Justice is also planning to build six new prisons – with the department stressing the benefits for the local economy in terms of job creation.

Raab, the justice secretary, said: “Our prison-building programme will deliver an extra 20,000 prison places by the mid-2020s to punish offenders, deter crime and protect the public.

“We are also overhauling the prison regime, using prison design, in-cell technology, abstinence-based drug rehabilitation and work to drive down re-offending.”

But the Liberal Democrat home affairs spokesperson, Alistair Carmichael, said the drive to build new prison places was an admission of failure.

“The UK already has more people in prison than any other country in western Europe, and now the government is spending an extra £4bn because crime is rising,” he said.

Peter Dawson, director of the Prison Reform Trust, said: “Endlessly making the same announcement about building new prison spaces is not going to solve the chronic failure of our prison system. For 30 years overcrowding and the continued use of prisons built in the 19th century have made a mockery of promises of reform. Nothing in the government’s plans changes that.”

The government was censured by the Statistics Authority earlier this month, for misleadingly claiming that crime has been falling. Boris Johnson and Priti Patel, the home secretary, had both said crime had fallen by 14%. The figures refer to the period September 2019 to September 2021, but exclude fraud and computer misuse. Once these are included, crime actually increased over the period.