Tough bio-security measures introduced to prevent the spread of foot-and-mouth in North Yorkshire have succeeded, Government officials claimed last night.

The Department for Environment, Food, and Rural Affairs (Defra) said the threat of disease in the Thirsk area had diminished because of the strict clampdown.

The most recent confirmed case of foot-and-mouth disease in the county was on August 7.

The bio-security measures were introduced in a Blue Box affecting 900 square miles of farmland in North Yorkshire on July 30.

The zone was created in an attempt to prevent the spread of the disease from Thirsk to pig farms across the Vale of York and beyond.

Under the clampdown, tough bio-security measures were introduced including stringent disinfection requirements.

A Defra spokesman said that farmers would still face restrictions on the movement of animals and urged the farming community not to be complacent.

He said: "The level of disease is now no greater than other parts of North Yorkshire. We cannot say it is free of the disease, that will take some time, but we are a step down the road."

From this weekend, police and trading standards officers will no longer patrol the area on the lookout for people flouting the measures.

Meanwhile, the number of suicides among farmers following the foot-and-mouth crisis is expected to rise through the winter.

At a major conference for mental health professionals near Bristol, about 80 representatives of the Mental Health Services Group heard that there was still a ''dreadful fear'' that foot-and-mouth disease would return.

The delegates representing NHS Trusts from around the country were taking part in the conference to look at mental health problems in rural areas, especially those in farming communities, to ensure they are taken into account in mental health policy.

Brian Warren, of the Farm Crisis Network, told the conference that mental health problems among those affected by the disease were likely to worsen over the coming months.

Mr Warren, a farmer in Devon, said many farmers were suffering from depression, had family and relationship problems, and some were turning to alcohol and drugs.

John Mahoney, the joint head of mental health at the Department of Health, gave the keynote address at the conference, in Failand, north Somerset.

It looked at the difficulties faced by mental health services around the country, and ways they could be improved.