A requirement to lower the speed limit outside Highpoint Prison will not be put in place as part of approved plans to expand its capacity.

The proposals for three four-storey housing blocks; a two-storey building for vocational education and workshops; additional industrial workshop space; a kitchen building; a healthcare building; a pharmacy; a car park, and an extension to the existing gym were approved by West Suffolk Council's development control committee on Wednesday.

During the meeting, some councillors expressed surprise over the Highway Authority’s acceptance of the 40mph speed limit on the A143 near Highpoint after objecting to the development in April.

It cited Suffolk Constabulary’s advice that reducing the speed limit to 30mph and adding speed cameras may be merited to improve safety – and the fact that nine reportable accidents occured near the site between 2017 and 2021.

At Wednesday's meeting , the Highway Authority’s decision to remove its objection to the plans was based on evidence from a speed survey conducted over one day by the Ministry for Justice, which found the development would not detrimentally impact capacity on the A143.

A representative from the Highway Authority said: “While there is evidence of highway safety incidents on the carriageway running through the prison site, there isn’t a lot of evidence to suggest the accidents are clearly associated with the prison.

“We pushed the prison on data about staff movements between Highpoint south and the facilities across the A143, and they evidenced that there is very little flow between them.

“They said staff do not customarily go to these facilities, and I believe this is because they would need to change their uniform and then put it back on when they return. But I’m not a prison officer, so I don’t know if that’s the case.

“The information provided to us through the speed survey was robust, which explains why we changed our position and recommended approval.”

Members of the committee also raised questions around the A143.

Nick Clarke, Conservative councillor for Clare, Hundon and Kedington, called for the approval to be deferred over safety concerns, telling the meeting: “The A143 is a fast, dangerous road. Locals know that cars in ditches make a regular feature.

“Somehow, between April and July, the applicants have convinced authorities that the objections can be lifted, despite speed cameras and a 30mph speed limit being required in April.

“Claiming an extra 700 prisoners along with visitors, staff, contractors and police will not add to the road safety issues already identified – it is nonsense.”

Councillor Peter Stevens said he could not support the application in its present form due to no public transport and the added pressure on Broad Road.

Independent councillor John Burns raised concerns about the lack of footpaths with prison staff seen walking along the grass verge to cross to the cafe and shops on the other side.

He said: “We are now going to have all these extra people at south Highpoint, and we’re not giving them any way to go and get their food or visit the shops easily.

“I would like to have seen the prison authorities thinking about their members of staff a bit more as part of this application.”

The vote was passed with eight councillors in favour, four against and three abstentions.