Manipulating the data in this way would also have allowed them to land around a third over their quota of cod in 2018, according to the group.

Programme director for Our Fish Rebecca Hubbard said authorities in England and Scotland seemed to be “turning a blind eye” to this problem.

“The UK government appears to be aware that large-scale unreported, illegal fishing for an important stock like cod is taking place within its fishing fleet,” she said.

“It is incomprehensible and indefensible that such rampant non-compliance would be simply ignored.”