Cell conditions at Lewes Prison are “an abomination in the 21st century”, according to the members of the public who monitor the running of the jail.

Shared rooms with open toilets are being kept under a planned refurbishment of 86 cells which is already seven years late.

Fears of rising prison numbers due to a recession-linked crimewave are behind the Government’s reluctance to cut the number of cells in the interests of decency.

The latest report by Lewes Prison’s Independent Monitoring Board criticised the decision not to improve the conditions in shared cells in the jail’s F Wing during a planned refurbishment.

It said: “This is an abomination in the 21st Century, an outrage to decency, and a wasted opportunity for improvement.”

Amanda Hamblin, chairwoman of the IMB, said: “We strongly believe that this arrangement should not proceed, that it is a contemptuous treatment of prisoners, and that it reflects badly on the prison service and HMP Lewes.”

In the crumbling Victorian F wing, about 150 prisoners share one-man cells, with a toilet in the middle of the room.

One 35-year-old former inmate, who did time on F Wing two years ago, told The Argus the conditions were unhealthy and degrading.

He said: “They should have the toilet doored off.”

The wing was due for refurbishment as long ago as 2002, but it has still not taken place.

Lewes governor Eoin McLennan-Murray said the prison would have preferred to follow the model of other wings and convert the middle cell of three into a toilet shared by the inmates on either side, ridding the cells themselves of open toilets.

The final decision is made by the Ministry of Justice - which last year had to house convicted criminals in court cells and police custody cells because the nation’s prisons were full.

Mr McLennan-Murray said: “Running the prison day to day on a decency agenda is a higher priority for me than the national prison population.

“I do understand the dilemma the Ministry of Justice have.

“What they would argue is that if you are keeping prisoners in police cells and court cells the conditions there are even worse than where there is a refurbished cell where there is a toilet.”

Overall Lewes, which has capacity for 723 prisoners, was described as “a humanely managed prison which has some excellent features and provides a safe and largely decent environment”.

Mr McLennan-Murray said: “I welcome the IMB report. I think it highlights many positive aspects at the prison.”

The IMB raised other issues including whether prisoners are properly searched for drugs and mobile phones, and whether rehabilitation programmes for alcoholics were adequate.

Mr McLennan-Murray said courses are in place to treat alcohol problems.

Nets have been put up over the exercise yard to stop the popular practice of people throwing drugs over the prison wall.

The Ministry of Justice declined to comment on any of the points raised by the IMB.

A spokesman said: “We are still considering the report so we can’t comment in detail before we have had a chance in detail to do that.”