A Yorkshire farmer has killed hundreds of piglets because labour shortages in local abattoirs mean adult pigs are not being killed fast enough.
The resulting backlog means there is less space left on farms for younger pigs, which are cheaper and easier to kill.
The farmer had been "destroyed by it", according to a friend.
"He had to kill perfectly healthy, viable piglets," she told BBC News.
According to the National Pig Association (NPA), this may well not be the only case of farmers killing healthy livestock as mature pigs have continued to "back up" on farms.
The labour shortages are being blamed on Brexit and the Covid pandemic.
Before that, about 80% of staff in two major processing centres in Hull came from Eastern Europe, according to the British Meat Processors Association (BMPA).
Nick Allen, from the BMPA, said the workforce in large abattoirs would normally be 10-15% above average ahead of Christmas, but instead it is 15% down. Because centres are unable to process pigs at the usual rate, live animals are mounting up on farms and some farmers were "quietly starting to cull", he said.
Once a pig gets too big, its butchered processed carcass will no longer fit into supermarket packets so retailers do not want to buy it from farmers.
"The main barrier is labour, with the change in the immigration policy. We are struggling to get butchers in particular, and it limits how fast you can run the plant," Mr Allen added.
"We were offering higher wages, but with the job market at the moment, it's not worked. We do need access to some non-UK labour."
Similar labour shortages among lorry drivers and poultry workers led the government to introduce temporary visas to try to limit disruption in the run-up to Christmas, but this concession was not extended to the pig-meat industry.
The Yorkshire farmer's friend, who did not want to be identified, told the BBC: "It's desperate. I've been producing for 26 years, and never faced the prospect of having to butcher pigs on my own farm before".
Meryl Ward who runs a family farm in Lincolnshire has 1,600 pigs that should already have gone to slaughter.
She has been farming for 35 years and says the current crisis is the worst she has encountered.
A humane cull, which is being discussed, would see prime healthy pigs being "rendered" for cheap products like lard or pet food, and farmers are unlikely to be compensated for their losses.
Parallels are being drawn to the 2001 foot-and-mouth crisis, where pyres of cows burned across the countryside.
She added: "Producers are in despair... we can't just waste this food. It's criminal."
She said temporary work visas were needed, like those recently issued for HGV drivers and poultry workers.
"It's such a massive national problem, it needs action and leadership from government.
"If they really care about farm animal welfare, if they really believe in UK animal production and the standards that we have are worth saving, we need some action," she urged.
A Defra spokesperson said the government was "keeping the market under close review" and continuing to "work closely with the sector to explore options to address the pressures" that the industry was currently facing.
The National Pig Association is urging retailers to back British producers, rather than to buy imported produce.
Supermarket chain Lidl described the backlogs as "alleged", adding it was "committed to" sourcing 100% of its fresh pork from British farmers.
Sainsbury's said all its fresh pork was British but that it "may source bacon and continental meats from the EU to meet demand."
Tesco said it was "working closely" with suppliers to make sure supply chains were protected to "provide availability" for its shoppers.
Aldi said its "core range" of meat was "100% British and Red Tractor assured."
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