"Could foot-and-mouth have led to the elimination of the dinosaurs" is just one of the mad questions from the media that Prof Chris Bostock, director of research at the Institute of Animal Health (IAH) in Britain, had to handle in the middle of the worst foot-and-mouth crisis Britain has experienced.

"Dealing with the media. . . it has been relentless. I was involved throughout the BSE, but this has been on a scale completely different and people have been obsessed with the most extraordinary and outrageous, in some regards, angles on it," he says.

Then there were the rumours that cultures or antibodies had somehow escaped from the Pirbright Laboratory, the world reference laboratory for foot-and-mouth disease, or had been stolen by animal rights' activists who had used them to spread the disease.

"A complete fabrication and mischievous," he says. "The current virus outbreak is distinguishable from all other viruses, subtly different. It's none of the viruses that existed before, although very closely related."

The name Pirbright is readily recognised these days: the laboratory that carries out all the testing for foot-and-mouth disease is part of the IAH. And as overall director of the IAH, Prof Bostock took responsibility for handling the media. You can tell it's not a role he relishes. However, he is a patient man, measured, cautious and helpful.

Pirbright in Kent has been an animal virus research institute, working on various aspects of exotic virus diseases - such as foot-and-mouth, blue tongue and African swine fever - usually not present in Europe but that pose a threat to European countries. Since the late 1950s it has been recognised by the Food and Agriculture Organisation of the UN (FAO) and the Office International des Epizooties (OIE) as the world reference laboratory for foot-and-mouth.

It also holds the international vaccine bank of antigen, containing seven highly-concentrated vaccine preparations for use in emergencies. Some 180 people out of 505 in the IAH are attached to Pirbright, working around the clock at present to confirm cases of disease.

While training scientists from around the world and liaising with institutes in different countries is standard work for Pirbright, the spotlight currently is on the various tests it carries out to determine whether the virus is present in herds or flocks.

The ELIZA is a 24-hour test using antibodies that recognise the virus and can give a positive result. The problem arises if it is negative or a weak/ doubtful positive, which is when a second test, based on primary cell cultures, is used. This test requires about five days and initially there were many complaints about the length of time it takes.

"People were getting very frustrated in the early days of the outbreaks. What they were hoping for was a negative, but to get that negative absolutely surely does take quite a while. The key thing is not to miss a positive. It's an extremely accurate and extremely reliable test."

When the Northern Ireland Department of Agriculture and Rural Development announced - on the basis of preliminary results - that cattle on the farm at Ardboe were clear of the disease, Prof Bostock was reported to have been very annoyed and forbade the release of any further preliminary tests.

"I'm not sure I was annoyed. Scientists may be different from politicians. There is tremendous pressure on scientists to divulge and discuss interim results. It's never good practice to anticipate the final results on the basis of preliminary results."

Although British politicians, from the Prime Minister down, are convinced the worst of the crisis is over, Prof Bostock believes nobody can really say.

"Being inherently cautious, one would say all the indications are there. . . numbers going down and the epidemic under control. One always has to be cautious and make all of the caveats, but from a scientific point of view it seems to be good news."

Serological testing will be used widely once the disease has waned to determine whether any animals were missed and have recovered and could still be carriers. "We're now tooling up to do quite large quantities of sero testing. We plan to get to a capability of doing something like 60,000 samples a week."

He doesn't believe the virus entered Britain through a live animal, but on a fresh meat carcass or a meat product. "I think it's significant that that first farm fed pig swill. That type of feeding inevitably carries the risk of recycling and transmitting infectious agents if you don't completely inactivate by cooking the pig swill.

"But where it came from, I don't know and I'm not sure. . . is it important? I sit on the SEAC [Spongifrom Enchephalopathy Advisory Committee] and we advised it was not good practice to be feeding pig remains back to pigs. We suggested pig swill should be stopped."

He points out, though, that current legislation may not cover such a ban and that it could lead to disposal problems for food outlets.

On the vexed question of vaccination, he is again measured in his views, but he comes out on the "anti" side. Vaccination is fine for countries where the disease is endemic, he believes. In a country such as Britain, emergency vaccination to form a fire break around an outbreak to allow for the orderly slaughter of animals, coupled with a "stamping out" or culling of infected animals, could be a useful tool.

But vaccination is against only one strain of the disease and the animals are susceptible to others. Current vaccines don't provide protection for very long and are expensive; while preventing an animal showing clinical signs of the disease, they do not prevent the animal becoming infected if exposed to the virus. And it can become a carrier - and then there is the problem of distinguishing between infected and vaccinated animals.

There are tests, he accepts, that purport to be able to differentiate between vaccinated and infected animals, but none has shown 100 per cent reliability. "They are a move in the right direction but I don't think they have got there and they certainly haven't been validated internationally and accepted internationally for trade purposes.

"One is no longer a complete entity in terms of international trade and one would have had to discuss the issue of vaccinated cattle being around in terms of our trade partners and the uncertainty about returning to free and open trade," he warns.

Born in Kent, Christopher John Bostock was "interested in biology as a child". After studying zoology, he became interested in molecular biology - then quite a new science - and worked for some time in the Medical Research Council on human genetic diseases and the sort of genetic bases of resistance to cancer drugs by cancers.

He then became interested in the structure of chromosomes "and changed field and went to the Pirbright Laboratory before the amalgamation into the institute to head up a new division of molecular biology".

"I never had a mission in life to do research as a career. One just gets exposed to different things, gets interested in different things and follows one's nose."