Mack, a three-year-old Springer Spaniel, was reported to the governor of Garth Prison by a jail officer who is in the RSPCA after the dead ducks were discovered, according to a national newspaper.

Until then, Mack had an impressive record of finding drugs at the category B prison in Ulnes Walton Lane, Leyland.

A spokesman for the Prison Service, said: "We can confirm that a drug detection dog at HMP Garth has been taken out of service pending an investigation into a complaint that the dog attacked a group of ducks.

"Drug detection dogs are regularly evaluated and any dog whose behaviour is of concern will be reviewed to assess its continuing suitability for the role."

A number of people have been jailed at Preston Crown Court in recent months after being found with drugs at Garth Prison.

Last June, visitor Garth Ball, 37, from Stalybridge in Manchester, was sentenced to three years and four months for attempting to smuggle in heroin powder. He was caught after a sniffer dog became suspicious.

And in November, mother-of-two Emma Barnes was trapped by a prison sniffer dog while trying to smuggle £2,500 of heroin to an inmate.

Barnes, 27 and from Warrington in Cheshire, was jailed for 21 months.

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