A cancer research specialist who waged a sabotage campaign against companies linked to an animal testing laboratory was jailed for three years yesterday.

Joseph Harris (26), a doctor of molecular biology, is the first person to be convicted under new legislation designed to tackle harassment and threats from animal rights activists.

Northampton Crown Court heard yesterday that Harris, was put in "an increasing moral dilemma" as his work was leading him to carry out tests on animals as he researched a treatment for pancreatic cancer.

He attacked three companies that were contracted to Cambridgeshire-based Huntingdon Life Sciences in December 2005 and January this year.

He broke into the premises of companies which supplied the firm with building materials, refrigeration servicing and testing equipment.

Harris, who was living in Nottinghamshire at the time he committed the attacks, glued locks, slashed tyres and put hoses through letter boxes at companies in Northampton, Nottingham and Bicester.

Harris, of Bursledon, Hampshire, pleaded guilty to three counts under the Serious and Organised Crime Act, which was brought in by the Government last July.

Jailing Harris, Judge Ian Alexander said: "I am sorry that your conviction and the sentence I impose will seriously damage what was a very promising career.

"It may well be that your future inability to continue your research into gastrointestinal cancer will be a great loss to those who suffer that disease."

The court heard Harris, a published author in his field, carried out his first attack, on a Nottingham refrigeration company on the day he was awarded his PhD.