Three people have admitted their involvement in blackmailing the owners of a Staffordshire farm used for breeding guinea pigs for medical research.

Kerry Whitburn (36) of Summer Road, Edgbaston, Birmingham; John Smith (38), of Leicester Street, Wolverhampton; and John Ablewhite (35), of Levenshulme, Manchester, admitted conspiracy to blackmail David Hall and Partners and others connected to Darley Oaks Farm in Newchurch, with menace during a brief hearing yesterday.

The trio had denied the offence and were due to stand trial later this month.

They were all remanded in custody following their appearance before Judge Michael Pert QC.

The three men have admitted conspiring together "with a view to cause loss to another" by making unwarranted demands for the closure of Darley Oaks Farm, where guinea pigs were bred for medical research.

A fourth defendant, Josephine Mayo, of Spring Bank Road, Edgbaston, will appear before the same court for a separate hearing today. She faces the same charge.