Criminals are using dead rats to smuggle the zombie drug Spice and phones into jail because the prison black market for them is so lucrative.

Three dead rats stuffed with drugs, mobile phones, chargers and sim cards were found by officers at HMP Guys Marsh in Dorset after being thrown over the prison walls, reports telegraph.co.uk.

The Ministry of Justice believe the extraordinary operation — disclosed today — was orchestrated by criminal kingpins through their organised crime networks.

Drugs in jails can fetch ten times the street price and generate further profits through repayment of debts for loans to buy them. One prison board member claimed even a single cigarette could cost as much as £100 on the black market.

Criminals have previously used tennis balls and pigeons to smuggle contraband into jails but it is thought to be the first time rats have been used.

They were disembowelled and their innards replaced by five mobile phones and chargers, three sim cards, cigarette papers and a large quantity of drugs including Spice, cannabis and tobacco. They were then neatly stitched up before being thrown over the prison walls.

The surge in Spice in prisons is blamed for spiralling violence. Rory Stewart, the prisons’ minister, said: ‘This find shows the extraordinary lengths to which criminals will go to smuggle drugs into prison, and underlines why our work to improve security is so important.

‘Drugs and mobile phones behind bars put prisoners, prison officers and the public at risk. By toughening security and searching, we can ensure prisons are places of rehabilitation that will prevent further reoffending and keep the public safe.’

Prison officials say scanners are key to  combating smuggling either through X-ray technology that can spot drugs or phones inside visitors’ bodies or Rapiscan machines which can detect drugs soaked into letters or paper brought into jails.

A prison board chief revealed one prisoner had tried to smuggle in drugs to Durham prison by soaking their hair in Spice so it could be cut and smoked.

One in five (20.4%) of random mandatory drug tests are now positive, half of which were accounted for by Spice, according to the latest MoJ figures. This is the highest level since 2006.

Assaults and violence in prisons are also at record highs. Assaults on staff were up by nearly a third (29%) to more than 10,000 last year, while prisoner on prisoner attacks rose by 18% to more than 24,000.

At some prisons, like Durham, two thirds of inmates say drugs are easily accessible. ‘In order to tackle drugs we need technology,’ said Chris Hutchinson, a board member at Durham prison. ‘There’s still a high level of people secreting packages in their bodies.’

The Ministry of Justice aims to introduce X-ray and drug scanners throughout prisons in England and Wales after successful trials of the technology.

Some £7 million has been earmarked for new security measures including scanners, improved searching techniques, phone-blocking technology and a financial crime unit to target the criminal kingpins operating in prisons.