Fresh British-grown vegetables will be in short supply this summer and shoppers can expect hefty price increases, horticulture experts have predicted.

The recent floods have damaged thousands of acres of broccoli, cabbage, cauliflowers,potatoes, onions and carrots. Last week the alert was over pea crops but now many growers are reporting losses of up to 70 per cent of their other vegetables.

The situation is described by Sarah Pettitt, the vice-chairwoman of the National Farmers’ Union horticulture board, as critical. It is also unclear whether imports from the Continent will make up any shortfall, because of similar problems with drought and floods across Europe.

The industry has decided to raise these fears now so that consumers can prepare for shortages and higher prices. In Lincolnshire and East Yorkshire, the area that supplies about 40 per cent of British produce, thousands of tonnes of vegetables are rotting in the ground, unable to be harvested.

The erratic weather continued yesterday. Two girls aged 13 and 15 were taken to hospital after being struck by lightning at Ipswich High School, in Woolverstone, Suffolk.

A spokesman for the East of England Ambulance Service said the force of the strike had “blown apart” the girls’ shoes. “They both had entry and exit wounds on their arms and feet,” he said. The girls, who remained conscious throughout, had suffered injuries that were not life threatening.

Commuters in southern counties of England had to travel home through hailstorms and torrential downpours which in some areas saw 7mm of rain fall in just an hour.

Areas of Yorkshire that were badly hit by last week’s flooding escaped the worst of the rain. Stephen Davenport, senior forecaster for MeteoGroup UK, the weather division of the Press Association, said more rain was expected over the next few days. “There will be a fair few heavy showers around tomorrow. On Thursday there will be rain coming in from the South West.”

That is further bad news for the farmers whose crops in the ground are already suffering signs of wet rot and which will not meet the standards of the supermarkets. Some growers doubt that they will harvest their fields at all, fearing that there will be little to salvage. New crops cannot be planted because of the wet conditions, and in some areas it may be 90 days before the soil will be drained and ready for new planting.

Industry experts believe that shoppers may start to see higher prices this weekend as firms seek to import stocks from theContinent. NeilBooley of Staples in Lincolnshire, one of the country’s biggest growers with 7,000 acres of vegetables, has had to buy in cauliflower from Spain to meet supermarket orders. The firm usually sends out 40,000 trays of cauliflower a week, a total of 320,000 cauliflowers. This week there are just 18,000 trays, some 144,000 cauliflowers.

Mr Booley is also worried about broccoli and is to visit Poland and Hungary next week to secure new supplies. Supermarkets buy broccoli for an average of 83p per kg and sell it at £1.25 per kg. The cost is expected to rise to at least £1.50 or £1.60.

Ian Grant, who farms near Boston, in Lincolnshire, said: “I usually plant a total of 200 acres of broccoli but so far only 30 acres are planted and they are just rotting in the ground.” Torrential rain and muddy conditions have forced organisers of the Royal Agricultural Show to cancel today’s events for the first time in its 168-year history. Numbers were down by 10 per cent and many believe that the future of the event is under threat.