Imported food coming into the UK through Brexit border posts is being sent back to Europe to be tested due to a lack of laboratory capacity in Britain, food bodies have said.

The SPS Certification Working Group, which represents 30 trade bodies covering £100bn worth of the UK’s food supply, has written to the government warning that members are being advised that some samples of imported foods are being sent to countries such as Germany to be tested before they can be released at the border.

It has said the lack of lab facilities was causing extra costs, longer delays and a shorter shelf life for food coming into the UK.

The letter, which was sent to the new environment secretary, Steve Reed, last week, comes three months after the government introduced new post-Brexit checks on animal and plant products coming into Britain.

The checks at border control posts situated near UK ports, which were brought in on 30 April, aim to enhance Britain’s biosecurity and stop the introduction of diseases into the UK from the continent.

In some cases, these checks require samples of food being taken to be tested in labs for microbial or chemical analysis, or to check the authenticity of a product.

However, the UK is now facing a shortage in laboratory capabilities and is more reliant on international partners for help with sample testing.

In a separate circular put out this month, Robin May, the Food Standard Agency’s chief scientific adviser, said he had concerns about the UK’s diminishing official laboratory capability.

The SPS Working Group letter states that in some cases samples are being sent to UK laboratories and then forwarded on to facilities in Europe, without knowledge or consent of the originating food business.

The body added: “This requires raising an export health certificate to export the sample to the EU laboratory, representing additional cost, delay, loss of shelf life, and viability of the use of the foodstuff, as particularly if short shelf life, results can also be too late to be of any practical value.”

The SPS Working Group was formed three years ago and includes a number of food businesses, from farmers to food producers and hauliers. Members include the Fresh Produce Consortium, Chilled Food Association, Dairy UK and the Road Haulage Association.

Their letter also highlights 18 other issues with the border process which it says are disrupting trade between the EU and Britain.

These include complaints that the opening times of most border control posts are too restricted and not conducive to 24/7 trade, while there is also a lack of 24-hour helplines for importers needing help.

The government’s Sevington border control post in Ashford, Kent, which serves imports coming through the Port of Dover, is the only 24/7 border post.

The letter also took aim at the costs being levied on importers bringing animal products from the continent, arguing that in some cases the high charges render some imports commercially unviable. Importers of food and plants have been hit by the charges on new border checks, with some logistics firms saying the changes have added up to 60% to transport costs.

It said: “EU exporters have stated that on expiry of current supply contracts they will review whether to continue to supply Great Britain given the new regime and associated issues.”

The letter also included analysis that revealed that UK food companies had forked out more than £205m on export health certificates since it left the single market.

After the UK officially left the single market at the start of 2021, the EU made it a requirement for exporters of foods of animal origin to have vets check consignments and sign export health certificates (EHCs) before they could be sent.

The SPS analysis, which is based on freedom of information requests to the Department for Environment, Food and Rural Affairs (Defra), found that more than 1m EHCs had been requested by exporters.

The UK brought in reciprocal measures in January, raising fears that some EU firms may abandon exporting to the UK owing to the extra costs and bureaucracy.

The UK government said it was confident it had testing laboratory capacity and it was common for laboratories to subcontract to other laboratories in instances where specialist testing was needed.

It added: “Protecting UK biosecurity remains one of our key priorities, and we are working with border control posts to ensure they operate effectively and with traders to ensure checks are completed efficiently, swiftly, and without significant delays.

“We’re looking to improve the UK’s trade and investment relationship with the EU and will take a pragmatic approach to support businesses.”