The exodus has left food processing plants unable to cope with a growing backlog of livestock – forcing farmers who are running out of space to cull thousands of animals. 

According to industry estimates, foreign workers previously accounted for two-thirds of a total workforce of about 95,000.

The shortfall is thought to be roughly 15pc. This prompted warnings that there would not be enough turkeys this Christmas and that pigs would be culled en masse.

Ministers have since introduced a temporary six-month visa scheme which they say will allow 800 butchers to come to the UK from next month and help clear the backlog.

But Mr Goodger warned that when their time is up the butchers will have to go home to do their English language tests before they can return.

He called for firms to be allowed a year to provide language training to recruits instead, with only those who subsequently fail a test sent home. 

George Eustice, the Environment Secretary, was challenged by the environment, food and rural affairs committee about the visa scheme last week.

MPs accused ministers of allowing food industry labour shortages to reach crisis point over the summer and autumn, despite concerns being raised as far back as February.

Mr Eustice said he had listened to concerns but blamed big food producers, who he claimed had failed to even apply for visas on behalf of butchers. 

He said: “Butchers have been able to come in under the skilled worker route. All you need is a sponsor, i.e. a business, to recruit those people and identify them and then sponsor their visa application. 

“The industry told us that they had attempted to recruit people through the skilled route but they had challenges with getting people with the right proficiency of English.

“I was very open at the time and said ‘Yes, I will raise this with the Home Office to explore it’. And the Home Office did look at that claim but found only one of the big four had even attempted to make an application through the skilled route.

“Ultimately, if there is a scheme there and a visa route available to businesses but they don’t even register to use it, there’s only so far we can take them.”