They work seven days a week. In summer, at least, they are on the go through all the hours of daylight. And they do all of this for no money.

And while they might not drive tractors, or care for animals, they are undoubtedly the most important agricultural workforce in the UK.

They're honeybees – and we are at risk of losing them and the vital services that they perform in plant pollination. That effort is estimated to be worth £200 million a year in production of fruit and vegetables.

Without the bees around there would be catastrophic declines in yields of apples, pears and many other types of fruit and vegetables. The situation would be horrifically unthinkable. But we could already be heading towards it.

For bee populations have been declining at alarming rates in the last few years. Repeated warnings by scientists and beekeepers now seem to have woken up the Government: it has now announced a £4.3 million research programme into the health of bees.

And, with the backing of some minor celebrities, it is also launching a 10-year Healthy Bees plan, which aims to identify and get in touch with as many as 20,000 beekeepers to encourage them to register on the national database and alert the National Bee Unit to health problems.

Official figures suggest that bee numbers are falling by between 10 and 15 per cent a year. But scientists say since so many beekeepers are not registered with the bee unit, the actual rate could be twice as high.

The cause is still not easy to identify. Bees have been under attack for some years by the tiny varroa mite which arrived in this country in the 1990s – and which, having once been beaten back by insecticides, is now developing a worrying immunity.

But the first signs are also being reported of so-called colony collapse disorder, where entire hives are suddenly struck by disease or even vacated, for no discernible reason.

This phenomenon was first recorded in the US where, in a single wave, it affected 875,000 beehives across 35 states, causing losses of between 35 and 90 per cent of the populations.

Bees have also vanished in Canada, Brazil, India and other parts of Europe, although the phenomenon is not entirely new: the earliest known instance dates from the 18th century. Disappearances in the US were also noted in 1869, 1923, 1965 and the 1970s.

One of the theories researchers are studying relates to the possibility of bees suffering catastrophic damage to their immune systems – though what might be causing that has still to be determined. Theories have ranged from agricultural insecticides to a succession of cool, wet summers and even to wireless waves from mobile phones.

Researchers in Britain and Holland (where the problem is just as acute) have already noted a correlation between a decline in wild flowers and the falling bee numbers which, they say, is too significant to be a coincidence.

The problem is as yet the research can't tell us whether the bee declines are causing the plant declines, or vice versa, or indeed whether the two are locked in a vicious circle in which each is affecting the other. But at least Government Ministers have now accepted the situation is far more serious than just the matter of dwindling honey supplies – most stocks of last year's English honey had been exhausted by Christmas.

The issue has also been taken up by the British Science Association. It is currently running a Save Our Bees campaign during National Science and Engineering Week and has managed to attract the support of half a million people for it.

More than 3,400 schools are expected to take part in bee-related activities during the week. They are being egged on by people like TV gardener Charlie Dimmock, who has also appealed to garden owners to plant bee-friendly shrubs to provide more forage for the insects.

Environment Minister Jane Kennedy said the first step in the Government's Healthy Bees campaign would be to improve contacts with all beekeepers to put them in touch with the free inspection and diagnostic services that the bee unit provided.

"That will help us pick up existing and emerging bee health problems and deal with them effectively," she said.

Somerset beekeepers' spokes- man David Morris said his members had been encouraged by the Government response and by the research cash allocation.

"We had asked for £8 million over five years but we are pretty confident that when this three-year programme comes up for review it will be extended," he said.

"We also asked the Government to appoint more bee inspectors: currently there are only two for the whole of Somerset and the former county of Avon – and the fact that we have now seen the jobs advertised is a very promising sign that this thing is being taken seriously."

In November, the European Parliament passed a resolution led by Conservative MEPs which urged the European Commission to fund extensive research into the potential causes of the sudden bee decline.

But Somerset Conservative MEP Neil Parish, who chairs the European Parliament's agriculture committee, says the cash earmarked by the British Government simply won't be enough to do the job properly.

"The Government has recognised the potentially devastating threat that the decline in bee numbers poses to our food security, but it will need to commit more than £4 million if we are to swiftly identify the causes of bee decline and remedy them," he said.

"The costs to our economy of not acting will be far greater than the comparatively small sum Defra has allocated so far.

"The declining bee population could have a detrimental impact on around a third of the food we eat, including most fruit and vegetables, which are pollinated by bees, and failure to take drastic action now could have serious consequences. There simply is no plan B."