An 88-page report, written by food policy experts, has warned that Britain is ‘sleepwalking’ into a post-Brexit future of insecure food supplies.

The report says the government is ill-prepared to deal without decades of EU regulations and that even if Britain remained part of the EU, agricultural and fisheries policies need major reform.

Prof Erik Millstone from Sussex University, who helped compile the study said: “We are surprised at the failure of the government to address a huge set of issues related to food and agriculture. They give the impression of sort of sleepwalking into this.”

While a hard Brexit could see food prices rise by up to 22 per cent, even a soft Brexit will hit “prices, quality, supply and the environment”, the report – published by SPRU, the Science Policy Research Unit at the University of Sussex – claims.