Crops could be left to rot in the fields as a result of a reduction in the number of seasonal foreign workers coming into the country, East Anglian farmers warned last night .

Crops could be left to rot in the fields as a result of a reduction in the number of seasonal foreign workers coming into the country, East Anglian farmers have warned.

For the last 40 years, thousands of non-EU students have flocked to the region during the harvest months to reap the rewards of plentiful agricultural labour.

But farmers spoke of their concern this week as tighter immigration policies presented the industry with a major shortfall of temporary migrant workers.

Over the last three years, the number of foreign workers coming to the UK from outside the EU as part of the government's Seasonal Agricultural Workers Scheme (SAWS) has been slashed from 25,000 to 16,250.

But under new rules coming into place next year, non-EU countries such as Russia and Ukraine will be unable to take part in the scheme - with all of its participants coming from Bulgaria and Romania.

The Home Office says the shortfall of seasonal workers will be made up by other eastern and central European workers who were given free access to UK jobs when their countries joined the EU in 2004.

However, farmers and employment- agency officials warned that the majority of the East of England's 65,000 migrant workers were looking for more permanent work in the building, manufacturing and catering industries.

Richard Hirst, chairman of the NFU horticultural board, who farms at Ormesby, near Yarmouth, said it was already becoming difficult to find workers to fill the current 40pc SWAS Bulgarian and Romanian quota for this autumn's potato, plum and apple harvests.

"There is a real risk that we will not have enough workers to plant and harvest our crops. There are a lot of farmers and agencies which rely on this labour because UK nationals do not seem to want to do it and there is a growing potential that crops will be left in the fields."

"From a horticultural point of view, SAWS is very important and has probably supported half of our labour needs for the last decade," he said.

Mr Hirst added that workers from the scheme were usually students from the Ukraine and Russia, who worked for a few months of the year on UK farms for up to £9 an hour while taking a break from their studies. Nationally, the NFU predicts that there will be a foreign-worker shortfall of about 5,000 next year as a result of the new SAWS rules.

Jamie Macdonald, director of Friday Bridge International Farm Camp, in Wisbech, a hostel for seasonal workers and employment agency, said its numbers had already dwindled from 500 to 350 workers over the last few years. He added that it was proving "hard work" to recruit new UK and EU labourers.

"It is jeopardising our business and the farmers' businesses. It is not a very green approach because if the government is not supporting local farmers, we will have to ship all our fruit and vegetables in," he said.

A Home Office spokesman said it was phasing out low-skilled migration from outside the EU because businesses "should hire people closer to home first".