Sainsbury’s boss Mike Coupe has warned that fresh food imports could be left rotting at the UK border post-Brexit.

Coupe said “anything that encumbers” the sourcing of food from the EU, such as strict customs controls, would have a “detrimental effect” on the freshness of goods coming into Britain.

“The UK sources roughly a third of its food from the European Union and food is by far and away the UK’s largest export,” Coupe told the Press Association.

“If you take our fresh produce supply chains, for example, we put things on a lorry in Spain and it will arrive in a distribution centre somewhere in England, and it won’t have gone through any border checks.

“Anything that encumbers that has two effects: it adds cost, and it also has a detrimental effect on freshness – if you’re shipping fresh produce from a long distance, even a few hours of delay can make a material impact.”

Coupe suggested that the repercussions of Brexit on supply chains are “not fully recognised” by the government, but said retailers and food producers would “make that point and make it very strongly” if a solution is not found closer to March 2019 – when the UK is due to officially exit the European Union.

His warning comes just days after the British Retail Consortium cautioned food prices could rocket unless measures to tackle red tape and improve ports are put in place before that deadline in 18 months’ time.