Inmates at an open prison have been popping Viagra pills - despite the shortage of female company.

The pills - which are used to cure impotence and enhance performance in the bedroom - were found in searches at the Category D Ford Open Prison near Arundel.

Ford's governor, Fiona Radford, said the discovery of Viagra is rare.

Prison staff believe inmates use the drug to perk themselves up for visits home and trips into town.

As Category D prisoners they are classed as the lowest risk, and many have jobs or are granted leave to go out unescorted.

Prisoners have gardening, vocational training, academic education and six snooker tables to take their minds off the parts only Viagra can reach.

Governor Radford said: "We do have town visits and home leave.

"It may be that they were using it for the purpose for which we all know it is used.

"We have got no indication there's any other nefarious use for them."

Ford, built on the site of a former Navy air support base, holds 541 prisoners.

The prisoner has been plagued by bad publicity over the last year, as it was revealed about 100 inmates a year, or two a week, escape.

The government sparked controversy with a decision to place more serious offenders in prisons such as Ford due to overcrowding elsewhere.

When told about the Viagra discoveries, Nick Herbert, MP for Arundel and South Downs, said: "If they're having so much fun in prison you wonder why they want to abscond.

"But the passing or smuggling of drugs is a serious matter and does appear to be on the increase."

In Parliament last month, he said prison officers at Ford had told him children as young as 15 were passing drugs into the prison.

He has expressed concern that use of class A drugs such as heroin and crack cocaine are on the rise in the prison.

The Argus used the Freedom of Information Act to obtain details about prison operations.

Between January 1 and December 31 last year prison officers confiscated drugs on 67 occasions.

The most common substance found last year was cannabis.

Apart from Viagra, other finds included heroin, steroids, DF118 (a form of the opium-based drug codeine), cocaine and unidentified substances.

A spokesman for the Home Office said: "All prisoners found with a controlled substance were placed on report to be dealt with by the adjudicating governor."

Prison officers also confiscated 12 blades and home-made weapons last year.

Many prisoners smuggle mobile phones into the prison, with 112 discovered in 2006.

One-fifth of those confiscations took place in December alone.

Staff use a hand-held detector to root out the phones.

Governor Radford said: "The vast majority of it is to contact their family and friends.

"In an open prison it is harder to keep them out than in a closed prison."