The UK government has said it will phase out the OTM (over thirty month) rule that bans older cattle from entering the human food chain and replace it with a system of testing for BSE, or mad cow disease.

The Department for the Environment, Food and Rural Affairs (Defra) said the main BSE public health protection measure - the removal of specified risk material (SRM), which is estimated to remove over 99% of infectivity in cattle - will continue to be rigorously enforced by the Meat Hygiene Service.

Defra said the incidence of BSE (bovine spongiform encephalopathy) has been declining since its peak in 1992 and has now fallen by over 99%. The numbers of new clinical cases detected are also at the lowest level since recording began. The government's Food Standards Agency (FSA) has advised that the current control measures are no longer proportionate to the risk.

However, Defra emphasised that an end to the OTM rule would not increase the risk of BSE-infected cattle entering the human food chain. Instead, it plans to establish a robust and independently audited testing regime; only cattle for which there is a negative BSE test result will be sold for human consumption.

"Protection of public health remains the government's priority. It is encouraging that the BSE epidemic in cattle has declined to its current low level, but we must remain vigilant and ensure that strict controls remain in place," said Secretary of State for Environment, Food and Rural Affairs, Margaret Beckett.

She added that the final phase-out of the OTM rule would not occur until the FSA is sure that the testing system is robust.

"This decision follows our successful efforts towards eradicating BSE in UK cattle. We will be developing a robust testing system. We will also be working in Brussels to ensure that beef from UK cattle born on or after 1 August 1996 can be exported as soon as possible after it becomes eligible for sale in the UK," Beckett said.

Any changes in the domestic OTM rule are unlikely to come into effect until the latter half of 2005. Changes in export restrictions are not expected to come into effect until late 2005.

The Over Thirty Month Rule has led to three quarters of a million cattle being rendered and incinerated every year. Cattle born on or before 1 August 1996 will remain permanently excluded from the food chain.