Labour shortages at meat processing plants have resulted in a surplus of 70,000 pigs on farms, the industry’s trade body has warned.

The surplus is growing by 15,000 a week and farmers are weeks away from having to destroy perfectly healthy pigs, according to Zoe Davies, chief executive of the National Pig Association.

It is blamed on an exodus of eastern European abbatoir workers, many of whom went back to their home countries after COVID-19 travel restrictions were eased but have not returned.

A shortage of workers at these plants reduces their capacity to process pigs meaning animals are left stranded on farms, growing fat and costing more money in feed.

At the other end of the supply chain, the bottleneck means some retailers are reducing the availability of some pork products on shelves or turning to EU suppliers to fill the gaps, Ms Davies said.

She called on the government to place butchers working in the plants on shortage occupation lists in order to address the immediate crisis.

“We have got weeks before we get to a critical situation,” Ms Davies told Sky News.

“We have to do everything we possibly can to prevent animals having to be destroyed.

“It is a travesty that this is happening because there are solutions that are within the government’s grasp.

“We cannot understand why they are not listening.”

Ms Davies said failing to resolve the situation would be the “ultimate betrayal” following the UK’s vote to leave the EU and called on retailers as well as the government to support British producers.

“If we end up having to import more rather than being able to bolster our own production, how ironic is that?” she said.

The issue, first reported by the Financial Times, is the latest example of a cocktail of supply chain problems that have been taking their toll on the UK economy and creating shortages of consumer products from Nando’s chicken to McDonald’s milkshakes.

They can be traced chiefly to a tangle of developments stemming from the pandemic and Brexit: COVID-19 alerts keeping workers from doing their jobs earlier in the summer; the shortage of an estimated 100,000 lorry drivers; and a lack of workers caused by European workers going home.

The National Pig Association’s cry for help comes a week after the British Poultry Council highlighted the problem of worker shortages following Brexit that were facing chicken and turkey processors.

Ms Davies said that in the pig processing sector, 80% of staff were from eastern Europe, and employers were now facing shortages of 15-20%.

She said these workers had first been worried about Brexit and what it meant for their status and the problem was then exacerbated by the lockdown.

“People weren’t able to go home then desperately wanted to go home. A lot of those people haven’t come back.”

Even some who had been granted settled status in the UK and started families were deciding to return to their home countries, Ms Davies said.

After a “mass exodus” of foreign workers it would take time to train British nationals to do the job, she added.

Ms Davies said that for consumers some ranges including pulled pork, ham products and UK-reared pork shoulder were among those being affected.

But there was also a “huge concern” about Christmas with producers battling to stay on top of day-to-day demand rather than beginning to prepare seasonal products such as pigs-in-blankets.