On Tuesday, probation officers voted in favour of strike action over the scheme, with probation union Napo saying 90% of its members had backed potential industrial action.

"This ballot wasn't about members being too busy," Napo national chair Ben Cockburn said.

"It was professionals warning they cannot protect the public properly when there are not enough people to do the work."

The MoJ said it was "disappointed" by the ballot outcome.

Inspectorate reports published between January and March 2026 highlight staffing gaps in probation, a lack of experience, significant issues with information sharing, as well as "the burden placed on overstretched staff by large-scale change programmes".

As of March, there were 5,554 full-time equivalent probation officers, a shortfall of 1,556 against the target staffing level of 7,110.

Prime Minister Andy Burnham has said there will be a presumption that all offenders released as part of the new laws will be tagged and have longer periods of supervision.

This will mean more responsibility on probation staff.

"Electronic tagging has been talked about as a key part of the arrangement but actually all that provides you with is information to inform their understanding of what is going on and then to act upon that when necessary, and I'm not sure the systems are there and robust enough to assist the probation officer when they're doing their work," Jones said.

"I've previously said that it would be a good idea to look at the overall workload of probation and consider what are the essential things that they need to be doing, not what's desirable."

"It's a matter of desirable work that I want the probation service to be doing.

"But with a probation service that probably has a vacancy rate of 20-25%, what can they realistically do."

On Tuesday, the prime minister said he was "increasingly confident" that work to add space in the prison system "will allow us to reduce the number of people released early".

It comes as Burnham is facing growing pressure to ensure the killers of PC Andrew Harper are not released as part of the scheme.

Downing Street had earlier warned it would not be possible to exclude "one or two offenders" convicted of manslaughter from early release.

But after an outcry, Burnham ordered the justice secretary to find a way to bar Jessie Cole and Albert Bowers from the scheme, and the prime minister has now said he is "confident" they can be excluded.

The letter welcomed the prime minister's intervention, adding: "This provides an opportunity not only to examine every lawful avenue in PC Andrew Harper's case, but to ensure similar concerns do not arise again."