ILLEGAL drugs valued at around £10,000 have been seized at Greenock’s Gateside Prison in the last three-and-a-half years, the Telegraph can reveal today.

The huge haul recovered by staff at the jail includes nearly £7,000 worth of heroin and more than 2,000 illicit tablets, according to official figures.

Prison officers also discovered 11 bladed weapons, a cosh and two other offensive implements in searches between 2011 and 31 May this year.

The data — released to the Tele under Freedom of Information laws — also reveals that more than 338 grams of cannabis was recovered during the time period.

The Scottish Prison Service (SPS) said today that the figures related to ‘apparent drug recoveries’.

A spokesman for the authority explained: “The apparent drug recoveries are unconfirmed and have simply been ‘field tested’.

“These substances are passed to the police for substantive testing and further action as appropriate.” The SPS was unable to reveal how many prosecutions have resulted from the various drugs and weapons seizures — or how much alcohol had been found during the 2011 to 2014 timeframe.

Officials cited cost limits — currently set at £600 per FoI request — as the reason for this omission.

A spokesman said: “Information on alcohol recoveries and prisoner prosecutions is not held on a format that is easily reportable.

“An individual would have to manually read 334 records to obtain the information, tabulate this and send to HQ for national tabulation in an appropriate format.

“Public authorities are not required to comply with a request for information if the authority estimates that the cost of complying would exceed the upper cost limit.” The Tele can reveal today that 95.9 grams of heroin was seized during the three-and-a-half-year period.

That puts the total street value of the Gateside Class A drugs haul at £6,720 — based on official Police Scotland pricing data.

A total of 2,219 ‘miscellaneous tablets’ were also recovered at the prison. Pills such as diazepam are known to be sold illicitly for 50 pence each.

Police Scotland put cannabis values at £5 per gram for resin and £10 per gram for the herbal form of the Class B drug, which means that the Gateside Prison haul is worth between £1,690 and £3,380.

The total value of all drugs seized at the jail within the FoI timeframe ranges from approximately £9,500 and £11,200.

Heroin recovered in 2011 totalled 58.6 grams, 11.4 grams in 2012 and 25.6 grams in 2013 — with just 0.3 grams being found between 1 January and 31 May this year.

Cannabis seizures reached a peak of 146.5 grams in 2012 and currently stand at 29.2 grams for 2014. So far this year, 138.5 illicit tablets have been found at the prison.

An SPS spokesman said: “These are substances which were recovered by prison staff over a three year period in small amounts. They were subjected to our own presumptive testing which only indicates a possible presence of an element.

“SPS takes the presence of drugs in prison very seriously and we have invested heavily in resources to tackle the problem.

“It is worthy of note that a recent prisoner survey highlighted that the percentage of prisoners who had ever used illicit drugs in prison reduced from 58 per cent 12 years ago to 38 per cent more recently. There is however no complacency on the part of the SPS.” Inverclyde Labour councillor Gerry Dorrian, a member of the prison’s visiting committee, today refused to comment on the figures obtained by the Tele.

His fellow visiting committee member, The SNP’s Keith Brooks, is currently on holiday.