Vaccination not a front-line defence against the virus

Instead, the contingency plans for dealing with an outbreak will see movement restrictions and controls on the midge population imposed to deal with the threat.

Currently a 20km control zone and a 150km surveillance zone have been set up around the infected farms in Suffolk, covering Cambridgeshire, Northamptonshire, Lincolnshire, Leicestershire and Essex.

Animals are not permitted to move out of the control zone except if they are being moved directly to slaughter.

If an outbreak is confirmed, however, steps will be taken to control the population of midges in the infected area, including the possible use of large sticky nets to trap potentially infected midges.

Further measures could include a curfew on animals, requiring susceptible animals to be kept undercover when midges are at their most active – usually the late afternoon and early evening.

Vaccination has so far proved successful in treating infected sheep in South Africa where the disease is endemic.

But EU research has ruled out use of the same vaccination in Europe over fears that using a live vaccine may introduce the virus to other, uninfected populations.

Developing an inactive vaccine is problematic because there are 24 serotypes of the virus and it is able to switch genes between serotypes, rapidly becoming resistant to new vaccines.

Vaccines are currently under development, but have been hit by delays due to production shut-downs at the Merial Animal Health research laboratory at Pirbright.

The centre is still not allowed to handle live vaccine after a leaked pipe the company shares with the Institute of Animal Health was blamed for the recent outbreaks of foot-and-mouth disease.

A spokesperson for Merial, Phillip Connoly said: “We started to develop a vaccine for serotype 8 six months ago and it's almost ready to go.

“We already have vaccines developed for serotypes 2 and 4 which work well and this one has also come through the trials. If we can get the go-ahead from Defra to get up and running at the end of October we should be able to get the vaccine out by early summer next year.”

Experts believe the best time to vaccinate would be in the spring before the midges responsible for the disease begin to swarm.

But without the go-ahead from Defra, Merial are unlikely to get the vaccine out in time to have the greatest impact.

Intervet also has a vaccine developed, but have not yet received permission to open a plant.

In addition, the European Union's health officials claim that even when a vaccine is finally released there may not be enough to treat the vast number of infected animals in Europe.

The European Commission's health spokesman, Philip Tod, said: “The vaccine won't be ready until early next year and it won't be ready for use until around spring.

“Even then demand is likely to outstrip supply substantially, causing shortages.”