One in every eight beef products tested in France were found to contain horse by a European-wide investigation into mislabelled meat.

None of the 150 products tested in the UK by the EU contained horse – in contrast to a separate national study which last month found horsemeat in about one per cent of 6,000 samples. However, the European Commission also tested more than 3,000 horse carcasses in the EU, Norway and Switzerland for the presence of phenylbutazone, the veterinary drug known as bute which is banned for human use. Fourteen of 836 horse carcasses tested positive for traces of bute in the UK, while it was present in 0.5 per cent of samples across the continent.

Officials said the high incidence in Britain was down to the testing of every horse slaughtered since February: most other nations tested less than 20 horses. Small amounts of the drug were found in Asda Smart Price Corned Beef last week, but European officials stressed the tiny levels of “bute” found in Europe were not cause for concern.