Sex offenders from across the South of England will be sent to Maidstone Prison in future, under plans to make it a centre of excellence for their treatment.

From June 30, the prison in County Road, Maidstone, will become a sex offender treatment delivery centre, housing almost double the number of sex offenders it currently takes, and also taking foreign nationals.

The change, which was approved by Minister of State David Hanson, will increase the number of sex offenders housed there from 174 to 334, plus 266 foreign national prisoners, bringing the total capacity to 600 – 11 more than at present.

The prison will remain a Category C training prison, but offenders currently housed at the jail for other offences will be moved to jails elsewhere in the country.

Sex offenders at jails around the South of England , including Lewes and Elmley, will be transferred to Maidstone to take part in its treatment programmes.

The prison is already recognised for its work with sex offenders, and has four specialist programmes.

Sex offenders who are eligible for day release have to go through stringent risk assessments. Many, who are governed by multi agency public protection rules.

It is 18 months since a damning inspection report found the prison had serious weaknesses, and new management was brought in. One wing, Weald wing, has been refurbished and extended, and will be handed back to the prison service on March 27.

One of the benefits to the prison, managers believe, will be that fewer drugs will be thrown over the walls of the town centre jail to inmates. Management had been struggling to tackle the problem.

Deputy governor Mark Taylor said: “We will be refocusing Maidstone Prison for staff, prisoners and local residents. Our main goal has always been to improve. We are a service provider to the public.

“Our interests rest with making our community safe and that won’t change.”

He added: “We envisage we won’t have the demand for drugs over the wall.

“It has been all systems go from day one for changing Maidstone for the better. We are quite excited about the change. It will be very promising for Maidstone and we are looking forward to the changes that lie ahead.”

Current staff will receive training to deal with the change in the prison population while specialist staff, currently based at Elmley on the Isle of Sheppey will be transfered, and the current specialist drug treatment staff based at Maidstone will transfer to Elmley.

Mr Taylor stressed that it would be a “natural transition” of inmates between now and June 30.

Martin Dacey, community engagement manager, added that the change would secure the future of the 190-year-old jail.

“With us being quite an old jail, when we have got a focus and a centre of excellence, it secures the future.”

Foreign nationals based at the jail will be those with more than 18 months remaining on their sentence, for a variety of offences, and it was expected that the new regime would mean both sex offenders and foreign national prisoners would be integrated and share activities.