Supermarkets chains in Britain have imposed limits on sales of some fruit and vegetables as grocery retailers face food shortages owing to extreme weather in Spain and Morocco – which cater to about 90% of the United Kingdom's tomato and lettuce demand during winter months.

Tesco, the largest supermarket chain in the U.K., said it is rationing the purchase of tomatoes, cucumbers and peppers to three per customer. Other grocery retailers like Asda, Aldi and Morrisons have also imposed limits on sales of some fruit and vegetables.

"This is due to poor weather conditions abroad and we're working hard with our suppliers to get things back to normal as quickly as we can," Tesco said in a Twitter post, adding it is limiting the sales of these fruit and vegetables so everyone can get what they need.

Spain has seen unusually cold weather while in Morocco crop yields have been hit by floods.

"At the moment poor weather conditions in Spain and Morocco have disrupted harvest for some fruit and vegetables including tomatoes and peppers, but rest assured retailers are doing all they can to sort it!" said the British Retail Consortium.

"Retailers are working hard to keep shelves stocked, and temporary restrictions, introduced by some retailers, will help ensure that stock lasts a little longer," the U.K. trade body added.

Asda has restricted sales of lettuces, broccoli, cauliflower and raspberries to three per customer, along with tomatoes, peppers and cucumbers. Morrisons has rationed cucumbers, tomatoes, lettuces and peppers to two per customer.

"We are limiting purchases of peppers, cucumbers and tomatoes to three units per person to ensure that as many customers as possible can buy what they need," Aldi said.

Retailers have cautioned that these shortages are set to last for weeks amid dwindling domestic production.

Minette Batters, president of Britain's National Farmers' Union, said that domestic production of cucumbers and tomatoes has fallen to its lowest level since records began in 1985. The National Farmers' Union has called for more support for UK growers, saying the horticulture sector was not included in the government's support scheme for energy-intensive industries.

In a YouGov poll, 61% of UK respondents said they have personally noticed or experienced food shortages in their local shop or supermarket in the last few weeks.

UK grocery stores

U.K. grocery stores ration fruit, vegetables as shelves go empty