The UK’s fishing fleets could face a de facto blockade within 48 hours of a no-deal Brexit, MPs have been told.

Representatives of the fishing industry said it was “a bit of an understatement” to describe the UK’s preparations for no deal as “a shambles”.

Not only is the country not ready, but there are not enough vets to stamp paperwork for every boatload of fish, which would be mandatory in a no-deal scenario, MPs heard.

“You could realistically be looking at the UK fishing fleet, certainly the fleet that’s catching exportable products, tied up within 48 hours of a no-deal Brexit,” said Terri Portmann, a marine consultant.

If trucks carrying perishable goods were caught in queues at Dover, this would have a knock-on effect at the daily fish auctions, with hauliers unable to pick up loads, she said.

“Would it not be an irony that the UK fishing fleet, who loyally, almost unanimously, voted for Brexit, got tied up because the government didn’t help and intervene to make sure the exports they so heavily rely on could continue,” she said.

The committee heard that about 50 lorries a day carry shellfish to the continent and that in a no-deal scenario, they would have to be accompanied by between two and four pieces of paperwork, including catch certificates, export health certificates, a process statement and a storage document.

The hauliers would also have to carry their own Brexit paperwork, including driver permits.

This would be likely to cause delays, as the staff at ports would have no way of prioritising fresh food in a queue of up to 10,000 lorries a day travelling between Dover and Calais.

MPs also heard that the UK lacks the army of vets and health authority officials who would need to be at the ready to certify the huge volumes of shellfish landed in Scotland or Northern Ireland for export to the continent.

“If you are sending fish from Northern Ireland on a land route across the short strait [Dover to Calais] you have to have that signed off by the vet before you load the lorry and then you’ve got anything from 24 hours plus transit time and you might normally be loading the lorry and sealing it at two or three in the morning. Are you going to be able to get a vet with your paperwork in time to do this?” asked Andrew Kuyk, the director general of the Provision Trade Federation, which represents the seafood sector.

The EU is also unlikely to allow fish through without the correct paperwork, MPs were told.

“There is a real risk that in a no-deal Brexit where our neighbours want to be less than helpful and merely enforce their regulations in a competent way, our exports could be stopped overnight because the catch certificates do not comply,” said Portmann.

“All fresh produce is time-sensitive. Live shellfish is very time-sensitive. Lorryloads of lobsters when they are dead and dying is not good news,” said David Jarrad, the chief executive of the Shellfish Association of Great Britain.

The committee heard that, while the government has indicated it has trained or is in the process of training 1,000 vets to be ready for no deal, there is little evidence of their existence or availability in the middle of the night.

In a scathing commentary on the government’s planning, Portmann said: “If the ambition of this government, through this process, has been to create a catch certificate system that we hope that nobody really checks or gives too much scrutiny to, to train 1,000 vets that aren’t really accessible or in contact with the industry, then the government has been successful in its planning.”