The health secretary has announced new measures to halt the possible spread of vCJD through the national blood service.

Amid fears that the disease can be spread by infected blood, the Department of Health is implementing a ban on donations from anyone who has received a blood transfusion since 1980.

Ministers expect the ban to affect around 50,000 blood donors.

Speaking in the Commons, John Reid said the risk of spreading the disease remained theoretical but said he would take no chances of spreading the disease through blood.

"The risk attached to this group of blood donors is of course uncertain but we are taking these measures as a precaution. The risk may be slightly higher than for the population as a whole," he said. 

Not proven

He urged the media to report the move in a "sober and non-sensational way".

The new regulations will come into effect on April 5 - allowing the service to replenish stocks ahead of a drop off in donations.

They come three months after the health secretary announced that a man who died from vCJD could have contracted the disease through a blood transfusion.

Reid said the government's approach was sensible but did not mean that there was solid proof that vCJD had be spread through blood transfusion.

"We are following a highly precautionary approach," he said.

The health secretary said the decision, which followed advice from the chief medical officer, would impact upon the supply of blood in the UK.

Speaking to the Commons he said the government would "increase our efforts in the more appropriate use of blood" in order to avoid shortages.