The Ministry of Justice (MoJ) said it was building more prisons while exploring early release options and expanding electronic tagging.
The figures come after Prime Minister Andy Burnham made more prisoners exempt from the upcoming early release scheme following backlash from victims.
Burnham came under further pressure after the killers of PC Andrew Harper would still be eligible for early release.
PC Harper, 28, was killed in 2019 when he was dragged by a car down a country road as three teenagers fled the scene of a quad bike theft in Berkshire.
Last week, Burnham said he was “confident” PC Harper’s killers could be excluded from the government’s early release scheme
On August 3, Burnham said in a written article, external he had “wanted to go even further” but had “pushed to the very limits of what is possible to do”.
A spokesperson for the MoJ said “public safety will always be our priority”.
“We are fast-tracking a plan to keep more of the most serious offenders behind bars, on top of murderers, anyone on life sentences and those in prison for rape, serious child sexual abuse and grooming offences who are already blocked from any changes,” they said.
“We share the public’s anger that these options are even being considered, after we inherited a prison system on the brink of collapse.”