Farmers are to hold a “drought summit” with government officials over fears Britain’s food supplies could be hit by the extended heatwave.

The first half of the summer has been the driest since 1961, with Friday’s wet weather the first rainfall the UK has seen in weeks.

Water shortages, a lack of fresh forage for animals and growing conditions for cereal crops are among issues that will be discussed at talks on Wednesday between the Department for Environment, Food and Rural Affairs (Defra), the National Farmers’ Union (NFU) and rural agencies.

NFU president Minette Batters described the situation as “hugely challenging” for all sectors of farming, warning that the thunderstorms and showers some areas were receiving “won’t mitigate the many issues farmers are experiencing”.

“There could be serious concerns for many farmers if this extended spell of warmer, drier weather continues as the long-range forecast suggests,” she said.

“This unprecedented spell of weather really should be a wakeup call for us all. It’s a timely reminder that we shouldn’t take food production for granted.

Theresa May dodges question on stockpiling ahead of Brexit

“Farming is one of the most affected industries when it comes to managing volatility.”

It comes as Theresa May has been forced to reassure voters over the government’s plan to stockpile food, blood and medicine in the event of a no-deal Brexit.

The prime minister said people should take “reassurance and comfort” from news of the plans, to be implemented if the UK crashes out of the EU without an agreement in March next year.

The scenario is looking increasingly likely given deep divisions in the Conservatives over Ms May’s approach, her wafer-thin Commons majority and the EU’s ongoing resistance to the prime minister’s proposals.

Historic sites across UK exposed by heatwave Show all 15 1 /15 Historic sites across UK exposed by heatwave Historic sites across UK exposed by heatwave Crop marks show of the old garden at Gawthorpe Hall, Lancashire Lancashire Council / SWNS.com Historic sites across UK exposed by heatwave Garden at Gawthorpe Hall, Lancashire which was taken out in the 1940's but can now be seen again through the parched grass Lancashire Council / SWNS.com Historic sites across UK exposed by heatwave Remnants of WWII Air raid shelters on Jesus Green in Cambridge show up in the parched grass SWNS.com Historic sites across UK exposed by heatwave Old crop marks in Norfolk show up Mike Page / SWNS.com Historic sites across UK exposed by heatwave Info showing how crop marks are made SWNS.com Historic sites across UK exposed by heatwave Old parts of RAF Lasham's airfield show up in the parched grass in Hampshire Jordan Bridge / SWNS.com Historic sites across UK exposed by heatwave Crop marks near Langstone, Newport RCAHMW / SWNS.com Historic sites across UK exposed by heatwave Crop marks show in Tregaron, Wales RCAHMW/SWNS Historic sites across UK exposed by heatwave Remnants of Caistor Roman town in Norfolk Mike Page / SWNS.com Historic sites across UK exposed by heatwave Penllwyn Roman fort in Ceregigion, Wales RCAHMW / SWNS.com Historic sites across UK exposed by heatwave Crop marks show in Tregaron, Wales RCAHMW / SWNS.com Historic sites across UK exposed by heatwave Old parts of RAF Lasham's airfield Jordan Bridge / SWNS.com Historic sites across UK exposed by heatwave Roman site near Magor, South Wales RCAHMW / SWNS.com Historic sites across UK exposed by heatwave Old crop marks in Norfolk Mike Page / SWNS.com Historic sites across UK exposed by heatwave Cross Oak hill fort in Talybont, Wales RCAHMW / SWNS.com

It comes as The Independent launched a campaign to give the British people a Final Say in a referendum on whatever is proposed at the end of Brexit negotiations, with hundreds of thousands flocking to sign a petition supporting the cause.

Those due to attend Wednesday’s summit alongside Defra include the Environment Agency, Natural England, the Rural Payments Agency (RPA) and farming charities the Royal Agricultural Benevolent Institution and Farming Community Network, the NFU said.

Last week the Environment Agency said it had responded to 44 “significant” environmental incidents since the end of June, including moorland fires, algal blooms, dry boreholes, low river flows and fish rescues.

The last month of dry, hot weather followed the driest June since 1925, the Environment Agency said. It has seen the water level in many reservoirs fall dramatically.

While only one water company is currently planning a hosepipe ban, continued dry weather into the autumn could see a risk of further restrictions and impacts on the environment, the National Drought Group said.