On Tuesday, the European Union lifted the ban on live sheep exports, following the declaration that the UK was now foot-and-mouth free.

Sheep are exported to Spain, Greece and Italy

Peter Stevenson, political director of Compassion in World Farming (CIWF), said animals travel to Greece, Italy and Spain on journeys of up to 90 hours.

He told BBC News Online: "They are packed in to overcrowded trucks and become increasingly exhausted and dehydrated.

"Some get injured and others collapse on the floor and get trampled on. In the worst cases, they die."

CIWF wants a complete ban on the trade but believes farmers need not suffer, because the animals should be slaughtered in Britain and the meat either exported or sold on the domestic market.

Cattle ban

Mr Stevenson said the farmers receiving public subsidies should respond to public concern and pull out of live exports.

And he accused the government of breaking its 1997 promise to support animal welfare.

A spokesman from the Department of Environment, Food and Rural Affairs, said an EU judgement prevented the government from acting.

He said: "We would prefer to see a trade in meat rather than live animals transported for slaughter, but a unilateral ban would be illegal.

Campaigners say the trade is cruel

"But they must be transported in accordance with animal welfare legislation and we enforce that and are seeking improvements in it."

Other speakers at the rally include Gwyn Prosser, MP for Dover and Tracy Sortwell, of the Women's Institute.

Last month, the EU's standing veterinary committee agreed to lift the ban on the export of live pigs. Cattle exports are still banned due to BSE.