Shoppers are being sold fish labelled as wild that has actually come from fish farms, according to a leaked report.

The report, which is expected to be published in the next fortnight, found samples of wild sea bass and sea bream had the stable isotopes of farmed fish, according to The Times. Samples of wild salmon from Italy and Norway was also found to have come from fish farms.

“There appears to be evidence, backed by authoritative scientific tests, that there is fraudulent selling and labelling in these particular markets,” a source told The Times.