Britain should opt to vaccinate poultry rather than slaughter flocks in order to tackle the threat of the lethal H5N1 strain of bird flu, according to a report issued on Wednesday by an organic research centre.

“Bio-security measures are an essential element of any strategy but the slaughter element is as outdated as British imperialism,” the Elm Farm Research Centre said in a report.

“A truly rational government would acknowledge that preventive vaccination is the most effective method of combating avian influenza in the modern world and would now be preparing to vaccinate all outdoor and organic flocks,” the report added.

Britain’s farm ministry has raised concerns about bird flu vaccines for poultry, arguing they can mask the effects of the disease and make it more difficult to tackle its spread among the poultry population.

The Soil Association, Britain’s organic certification body, distanced itself from the report, issuing a statement supporting “strategic” but “not preventative” use of vaccination.

It backs vaccination only under limited circumstances, such as if culling fails to control the disease or if the virus becomes endemic in Britain’s wild birds.

Last week Britain’s farm ministry issued a tender for 10 million doses of bird flu vaccine while stating its policy had not changed and it would not vaccinate poultry in advance of a bird flu outbreak.

The ministry said the move was part of “sensible contingency planning in the light of uncertainties relating to the future spread and nature of the virus.”

Britain currently plans to house all birds for a limited period in areas where the bird flu virus has been found and slaughter affected flocks. If the disease became endemic in an area, flocks could be kept indoors indefinitely.

“This is an apparent willingness amongst politicians and officials to ignore animal welfare by permanently housing outdoor birds thereby destroying the free-range and organic markets in an attempt to maintain an outmoded disease free status for the nation,” the report said.

The European Union has allowed Europe’s two largest poultry producers, France and the Netherlands, to vaccinate hens, ducks and geese against H5N1. Very few producers have, however, taken up the option.

There has been only one confirmed case of the H5N1 strain in Britain in a wild swan, found dead in early April. There have been no cases yet in domestic poultry.

H5N1 has, however, spread rapidly since late 2003 from Asia to Europe and Africa with outbreaks confirmed in more than 48 countries and territories, according to data from the World Organisation of Animal Health.