The worst seasonal labour shortage to hit Britain for decades could mean thousands of tonnes of fruit and vegetables, worth millions of pounds, left to rot in fields.

Recruitment agencies have seen a 30% drop-off in interest from eastern European countries and farmers are fighting a desperate battle to attract foreign labour. But, with harvest under way in some parts of the country, and others just a fortnight away from picking, it appears to be a losing battle.

In Scotland alone, up to one-fifth of the soft fruit crop, worth £5.2m, could be lost.

The once-plentiful supply of labour from countries such as Poland and Latvia is drying up. Put off by last summer’s dreadful weather and the weakening pound against the zloty, Poles don’t want to come to the UK, preferring to stay at home, where wages have risen by 13%.

Rob Orme, director of recruitment agency Concordia, said time was running out.

“Last year saw a decline of about 20% in the number of students coming forward for seasonal work,” said Mr Orme. “This year that decline has worsened by another 30%.”

But it is not just the exchange rate and the weather that are at the root of the problem. Politicians, eager to cut immigration figures, have reduced the number of students allowed into Britain under the Seasonal Agricultural Workers Scheme.

“SAWS underpins the seasonal workforce, but the number of students allowed has been cut from 25,000 to 16,250 this summer,” said Mr Orme.

“The scheme is also restricted to Romania and Bulgaria this year, ruling out countries like the Ukraine and Russia, where there is still keen interest in working in Britain.

“Like the Poles, Bulgarian and Romanian students simply don’t want to come in the numbers we need.”

A call to temporarily extend SAWS to allow 5000 nationals from non-EU countries, where demand for seasonal work still remains strong, was rejected last week.

Case study

Strawberry growers Charles Kidson and Carol Critchley of Lower Reule Farm in Staffordshire said the situation was critical.

“We have been to Poland to recruit,” said Mr Kidson. “We may just have the 250 pickers we need. But for every 10 who say they will come, only six or seven are actually turning up. We should begin picking in two to three weeks. It’s getting really close.”

Mr Kidson has urged his MP to call for urgent action on extending SAWS to non-EU countries.

“The SAWS scheme has run efficiently for decades,” he said. “It is a model scheme. About 98% of students who come over return home after six months to pick up their studies.

“Politicians need to be told that this is not an immigration problem – it is a carefully controlled scheme where everybody involved wins.”

Ms Critchley said it was frustrating that workers in some countries were keen to come but were being prevented by the changes to SAWS.

“It is having a huge impact. We could still find ourselves 30% down on numbers, which could have a catastrophic effect on our harvest. The season so far is behind because of the cold start, but that will have the effect of bringing on the crops at the same time. July is going to be very difficult.

“We will have to look at each field in turn, assess the crop, and in some cases we may have to simply walk away.

“We grow for Tesco under a local label. Tesco will go short of local British produce because of government policy. The space will be filled by imported food instead. It is a heartbreaking thought.”

Sharon Cross, operations manager of G’s Marketing near Ely, Cambridgeshire, said: “This year is the worst we have known.

“We need another 100 people to make up the 1200 we need or we will have to leave some crops unharvested.

“Field work is under way here and time is running out.

“We are desperately, desperately, seeking workers. Contracts are being signed but when it comes to it, the students are simply not appearing.”