The Sussex countryside is being devastated by the blue tongue outbreak and may never recover, experts have warned.

A report by the South Downs Joint Committee, the conservation group which manages the protected area, said the virus was a severe blow to already beleaguered livestock farmers.

It predicted a shift to arable production, meaning the sight of lambs grazing on the South Downs could become a rarity within years.

The blue tongue virus, which affects mainly sheep but also cattle and goats, is common in North Africa and southern Europe but spread to Britain last year.

It is transmitted by midges and farmers had hoped a cold winter would kill off the insects.

But the mild weather has sparked fears the midges could survive the winter - and cause havoc in the summer months as they did in Holland in 2006.

Last year Sussex farmers were hit by export and movement restrictions enforced by the Government in the wake of blue tongue and foot and mouth outbreaks.

In October, blue tongue disease was diagnosed in two rams at a farm in Northiam, near Rye, which led to an exclusion zone being set up.

The sheep industry was already facing an economic crisis before the outbreak. Farmers were reporting losses of £37 per ewe after prices fell by almost 30 per cent on 2006 prices.

Martin Beaton, the committee's South Downs officer, said: "Blue tongue has had a significant impact on the economics of sheep farming, which was already under significant economic pressure.

"The impact of the virus is likely to continue in 2008, and will affect the economic performance of the sheep industry.

"Poor sheep prices coinciding with improved arable prices are likely to drive the expansion of arable production."

Last month, the Department for Environment, Food and Rural Affairs ordered 22.5 million doses of blue tongue vaccine for at-risk areas, including parts of Sussex.

It wants to ensure it will be available by summer to control the impact of the virus and ease movement restrictions on vaccinated animals.

Lewes MP Norman Baker, who met farmers in Firle yesterday, said the move was not enough.

He said: "Blue tongue was a problem the Government should have got to grips with a lot earlier. With that, foot and mouth and TB in cattle, livestock farmers are really up against it and are asking how they can carry on.

"The Government has a blue tongue restriction between some areas in Sussex, so I have spoken to farmers who can't move their own sheep from Wealden back into Lewes. It's ridiculous.

"I am collating information and views from local farmers at the moment. We must not allow this problem to drift."

simon.barrett @theargus.co.uk