The public won't allow a cub cull, and anyway what good would it do?

An adult grey seal eats several kilograms of fish a day and the seal population has almost doubled in Britain in just 10 years. So it's not surprising that many fishermen hate them.

There are two problems in trying to control their numbers. First, the only way to make any impact on their population would be to organise a mass cull of the young pups during the breeding season, shooting them on the beaches at point-blank range. Adults flee into the water when humans approach, and they are extremely difficult to shoot en masse in the sea. The Government could grant licences for a cub cull but it is hardly likely to, given the animal-loving nature of the electorate.

In 1978, the Scottish Office, under strong pressure from fishermen, gave licences and brought in a shipload of seal-shooters from Norway. Greenpeace organised a highly successful protest in Orkney and the then Prime Minister Jim Callaghan, whose office was inundated with protest mail, called the cull off.

Second, killing the seals might make the fishermen happy, but there is no certainty that it would leave any more fish for them. Dr John Harwood, who heads the Government's Sea Mammal Research Unit in Cambridge, points out that alternative fish predators could fill the gap if seal numbers were reduced. Other fish, seabirds, dolphins and even whales (there are about 3,000 fish-eating minke whales in the North Sea) are out there competing with the fishermen.

The grey seal - the more numerous of the two British species - is known to eat commercial species such as cod. It also takes the prized wild salmon in estuaries and around salmon nets and bites salmon swimming inside the cages of fish farms. This has prompted the development of underwater sonic scarers which soundwhen any seal comes near.

Seals are also hearty eaters of sand eels, a tiny fish near the bottom of the North Sea food chain which forms up to half their diet. Dr Harwood says it makes little sense to organise culls in the absence of any firm information about how seal and commercial fish populations are linked. The unit plans research in this field over the next few years.

Seals are only protected by law during the breeding season - from 1 September to 31 December for greys and from 1 June to 31 August for the smaller common seals. Protection laws date back to 1914, when commercial and sport hunting had reduced the grey seal population to a few hundred.

Outside these periods anyone can kill them, with a few exceptions. Fishermen can shoot them all year round if they are seen to be next to their nets. Several hundred are shot each year but this makes no impact on their thriving populations.

There are 110,000 grey seals along the British coastline - about half the total world population - and their numbers grow by 4 per cent each year. Britain has about 28,000 common seals and they are legally protected all year round along England's east coast. This is because they were hard hit by the great seal epidemic of 1988, a viral disease that wiped out a large proportion of the North Sea's total population.