Veterinary experts are investigating biosecurity at the organic farm at the centre of the current avian flu outbreak amid fears that the H5N1 virus has already spread to two nearby farms.

Industry sources said last night that workers at Redgrave Park Farm, near Diss, Norfolk, had also spent time at the other farms, both of which are within the 1.9-mile (3km) protection zone. It is being suggested that routine cleansing and disinfecting between holdings was not a priority and that facilities were basic.

There is concern that 45,000 free-range geese may be infected. Fred Landeg, the acting chief veterinary officer, said that an immediate cull would be ordered if there was any evidence that there had been “dangerous contacts” between flocks and farms.

There was disbelief in the poultry industry and among ornithologists that, despite government warnings of the high risk of avian flu transmission during the spring and autumn migration periods, the free-range birds were not kept away from wild birds at an ornamental lake on the farm.

Redgrave Poultry, a subsidiary of Gressingham Foods, which runs the farm operation, said that it had tried to keep the birds separate but that there were circumstances when wild birds could mingle with free-range turkeys. However, the Royal Society for the Protection of Birds said that the Government stepped up testing of wild birds this autumn and not one tested positive for the virus.

Dr Landeg called on poultry keepers and hobby farmers to be vigilant and to maintain rigorous disinfection procedures. They should also report any suspect symptoms in their birds. He called on those with flocks of fewer than 50 birds to sign the Government’s poultry register to get updated information about the disease.

Dr Landeg is keeping an open mind about the source of the disease and checks are being made on the movements of people and vehicles to see if there is any link with southern Germany or the Czech Republic.

The virus can be spread easily on lorry tyres or crates used for transporting birds if they come into contact with infected faeces. Some birds arrived at the premises about a month ago, but their origin is not yet known. Other poultry companies are conducting audits to see if they may be linked with the infected premises.

Bernard Matthews, which is just recovering from the H5N1 outbreak that hit its Holton turkey plant in February, disclosed last night that it had suspended contracts with litter and feed suppliers that conducted business at Redgrave Park Farm.

Redgrave Poultry has made clear that no birds from the farm had entered the food chain. The infected bronze turkeys were eight weeks old and due to be slaughtered in the week before Christmas.

Hilary Benn, the Rural Affairs Secretary, told MPs that officials were doing their utmost to make sure the disease did not spread, but that there could be other undisclosed cases in the area.

The Tories accused the Department for Environment, Food and Rural Affairs of financial mismanagement because, they claimed, local authorities were being forced to slash animal health budgets this year despite a series of farm animal disease crises.

Production line

860m Number of chickens reared for the table in Britain each year

1.3m Tonnes of chicken meat produced from these birds

17m Turkeys reared for meat

19m Ducks reared for meat

100,000 Geese reared for Christmas market

23kg The amount of chicken meat eaten by the average Briton each year, plus 3kg of other poultry, such as turkey, duck and goose

£3.5bn The total value of poultry retail, of which fresh chicken accounts for £2.1bn

£375m What the Christmas turkey market is worth

20 weeks The lifespan of a free-range turkey – factory-farmed birds are slaughtered from 12 weeks

Source: Times database

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