Almost half of England has officially been plunged into drought after a succession of sweltering heatwaves has resulted in the driest July on record.

The Environment Agency has declared drought across seven regions spawning central, eastern and southern England, warning the country is now using water faster than nature can replace it.

Farmers say the prolonged dry spell is already damaging crops, forcing supermarkets to push up prices – and could even lead to shortages of some vegetables, including baking potatoes.

The areas now officially in drought are East Anglia, Hertfordshire and the entirety of London, the Thames Valley, Hampshire and the Isle of Wight, Devon and Cornwall, the West Midlands, and Wessex, which covers Dorset, Somerset, Wiltshire, and Gloucestershire.

England has received just 7% of its average July rainfall, while southern England has seen only 1% of what would normally be expected.

The Environment Agency said the combination of a dry spring, a hot summer and repeated heatwaves has triggered a “flash” drought, despite reservoirs and groundwater being replenished by a wet winter.

The announcement comes as parts of the UK endure a fourth heatwave of the summer, with temperatures climbing into the 30s.

Three earlier wildfires have already fuelled wildfires, damaged rivers and wildlife, hit agriculture and prompted hosepipe bans affecting millions of people.

Many farmers say the impact is already severe. Paul Francis, of Long Farms in Suffolk, said the lack of rainfall had significantly reduced yields of rapeseed, potatoes, onions and carrots, with vegetables also expected to be smaller than usual.

“You feel helpless,” he said. “England is usually good for enough rain for crops and we work hard to grow them but the weather can spoil it.”

He warned there could be shortages of baking potatoes and onions this year, adding that supermarkets should increase prices to better support farmers facing mounting losses.

National Farmers Union deputy president Paul Tomkins said: “Farmers and growers have always had to contend with the weather, but what they are experiencing now is climate change in action.

Read More: ‘Flash drought’ declared in half of England as heatwaves result in driest July on record