Apply for a lump sum payment to leave or retire from farming
gov.uk
gov.uk
Entering a time period where food insecurity might be a real thing, reducing the number of farmers doesn’t seem like the wisest course.
this is the ostensible reason
my guess is that it's a bit more complicated. as that article says - the average farmer gets paid 21,000 pounds from the government. I know in america subsidies keep the prices of certain crops stable. My guess is that these programs are very costly to run and often times it is cheaper for government to tell people to stop farming than continue on with their promises of paying for crops no matter demand levels.