A parents' action group has vowed to oppose moves to build a new block for 40 extra sex offenders at Albany Prison near Newport.

Albany is already one of the country's main jails for vulnerable inmates, who are mainly sex offenders, and now planning consent is being sought to build a two-storey block for 40 more.

The prison can currently house up to 446 inmates, and the extra block would increase its capacity to close to 500.

The Home Office has confirmed that the extra inmates would be of a similar type to those already at Albany.

Planning consent for the extra block - described as "to help cope with an unprecedented rise in the prison population since Christmas" - is to be considered by Island council planners next Tuesday.

The application was submitted under a "special urgency" notice by the Home Office on April 11.

Lynn Hammond, spokeswoman for the Isle of Wight Parents' Action Group, said she was appalled that more sex offenders were likely to be housed on the Island.

She said the group would strongly oppose the application. In recent years the group has highlighted what it says is an increasing number of sex offenders, originally from the mainland, staying to live on the Island when they are released.

A series of marches was staged several months ago to protest at moves under the government's Homelessness Bill to give released inmates housing priority.

Mrs Hammond said: "We as a group are very concerned by the number of sex offenders staying here already, and increasing the numbers at Albany would make the problem far worse."

She said the group estimated there were about 300 resettled sex offenders already on the Island.

"It is constantly denied by the authorities that more and more are settling here when leaving Albany, but we have the names and addresses.

"This planning application adds to our fears already expressed in connection with the rehousing issues under the homelessness legislation."

The planning application states that the new block will be two storeys high, with a single-storey ancillary building, altogether providing room for 40 more inmates.

Council officers are recommending that no objection should be raised to the application on planning grounds. Other areas of objection are outside the planners' scope.

Albany is the newest of the Island's three jails, built in the 1960s, and a maximum security prison until 1992.

From 1992 to 1997 it was divided into a two-regime establishment, for both mainstream inmates and sex offenders. Since then it has been run as a safe prison for inmates who may be vulnerable elsewhere.

One of the jail's most notorious former inmates was paedophile Sidney Cooke.

Recent reports have praised the jail for its treatment programmes for sex offenders.