NICK BROWN, the Agriculture Minister, has received death threats from animal rights activists in protest at badger culling trials. Whitehall sources confirmed the reports yesterday but said that the minister was not prepared to give details. A spokesman made clear, however, that Mr Brown was unmoved by the intimidation and remained committed to the trials. He has told staff: "I am going to see it through."

But The Times has learnt that he is so concerned by the widening of attacks and threats by animal rights campaigners against people involved in the trials that he has asked Jack Straw, the Home Secretary, for a stronger police response.

The badger trials are a five-year study to test whether there is a link between the animals and tuberculosis in cattle. Mr Brown wants to find out whether culling badgers in a particular area has any effect in reducing cases of bovine TB.

Farmers have reported instances when their children have been followed from school by activists. Ministry of Agriculture staff have also been threatened for taking part in the trials and tyres of their vehicles have been slashed.

There is also concern in Whitehall that chief constables may have deliberately adopted a "softly, softly" approach to the lawbreakers.

Mr Brown has asked Mr Straw to ensure that police share information about individual activists so they can be arrested and prosecuted for their unlawful activity.

There have been sustained campaigns and disruption to the trials in Gloucestershire and Wiltshire. The Ministry of Agriculture is operating a news blackout about the trials in an attempt to halt the disruption.

Ben Gill, president of the National Farmers' Union, is adamant that the activists who are threatening farmers should be dealt with under the law as terrorists. He said yesterday: "I am concerned about the badger and also GM crop trials. These activists are in a different bracket and are guilty of clear, absolute terrorism."

The badger trials started two years ago and are taking place in ten areas over the next five years. Two sites have yet to be named.

Trials so far have been on the Gloucester-Hereford border, Devon and Cornwall border, East Cornwall, East Hereford, North Wiltshire, West Cornwall, the Staffordshire-Derbyshire and Devon-Somerset borders. However, many farmers are becoming increasingly anxious about the rise in TB numbers and believe there should be a full-scale badger cull. Pat Stanley, who farms nearly 1,000 acres with her husband John in Leicestershire, is particularly concerned that the rapid spread of TB could destroy her prize pedigree herd of Old English Longhorn cattle.