Britain will see "food rotting at ports," unable to be transported to shops and the consumers who need it if the UK falls to avoid a cliff edge Brexit, a major industry body has warned.

In a letter to Prime Minister Theresa May and chief EU Brexit negotiator Michel Barnier, the British Retail Consortium (BRC), warned of chaos at ports in such an event.

The UK to imports roughly one-third of all its food from the European Union.

LONDON — Britain will see "food rotting at ports," unable to be transported to shops and the consumers who need it if the UK fails to avoid a cliff edge Brexit, a major industry body has warned.

"It is time for a reality check on the damaging consequences for millions of UK consumers and tens of thousands of EU-based producers if we fail to reach an agreement in the Brexit negotiations that protects the free flow of goods between the EU and the UK," a letter from the British Retail Consortium addressed to both Prime Minister Theresa May and chief EU Brexit negotiator Michel Barnier said.

The letter, co-signed by the BRC's Chairman Richard Pennycook, and CEO Helen Dickinson, calls on the two sides of Brexit negotiations to preserve the "fragile" supply chain that allows the UK to import roughly one-third of all its food from the European Union.

Under the current system, trucks and ships coming from the EU to UK ports and vice versa face virtually no impediments, meaning they are able to travel freely across the channel and deposit food wherever needed.

If Britain drops out of the EU without a deal — as many believe is now a distinct possibility — the arrangements in place to allow that will immediately cease to apply, likely causing chaos at Britain's ports.

"Failure to reach a deal – the cliff edge scenario – will mean new border controls and multiple ‘non-tariff barriers’, through regulatory checks, that will create delays, waste and failed deliveries," the BRC's letter to May and Barnier said.

"The consequences of this will be dramatic for UK consumers. It is likely that we will see food rotting at ports, reducing the choice and quality of what is available to consumers," it continues.

The possibility of customs checks for vehicles coming into the UK from the EU post-Brexit has been a topic of contention throughout the last couple of years, with industry bosses warning almost since the day after the vote that failure to implement a new customs system would lead to massive problems with the movement of goods.

Not only will failure to reach a deal on the movement of goods hit UK consumers hard, but the BRC warned that it could be a costly issue for food producers in the EU.

"The consequences for EU producers and the countries from which they export will also be severe. EU-27 businesses face losing £21 billion of agri-food exports to the UK," it said.