The much-maligned polytunnel - demonised by rural campaigners such as celebrity gardener Monty Don - turned hero this week and saved the UK's strawberry crop from floods that deluged northern England.

Torrential rain across parts of the country left towns under several feet of water and also flooded strawberry farmers' fields.

But, thanks to the widespread use of plastic polytunnels by growers, soft fruit crops that might otherwise have been washed away were spared damage.

Activists such as TV star Don say the tunnels are an eyesore and have called on planning authorities to control their use.

But National Farmers' Union chief horticultural adviser Philip Hudson said events this week had proved how important they were when it came to protecting the UK's 48,000-tonne strawberry crop, which is worth £200m a year to Britain's growers.

"Rain like this would have destroyed around 40% of the crop before the tunnels provided cover," he said.

But there was bad news for pea growers. Birds Eye said it expected yields to be down 10% due to the floods.

Retailers were also affected by the floods, which hit Yorkshire, Lincoln­shire and the Midlands the hardest.

Fifteen inches of water and silt swept through Tesco's store in Rotherham, South Yorkshire, after the nearby River Don burst its banks. The store closed late Monday afternoon and reopened on Thursday.

A Morrisons store in Hull was forced to close for 24 hours because it had flooded, while two stores, in Rotherham and Retford, were closed, the former for two-and-a-half days, because their car parks were submerged. Both have since reopened.

Sainsbury's said six Local stores had temporarily closed.

Asda stores were unaffected, but its headquarters in Leeds had a narrow escape. The nearby River Aire rose seven feet, but did not burst its banks.