The personal details of farmers carrying out the controversial badger cull have been leaked to animal rights activists in a major data breach.

In a security failing hailed a victory by hunt saboteurs and already linked to a rise in rural crime, more than 7,000 names and addresses, including those of bosses of companies specialising in killing badgers, have been posted online and emailed to activists throughout the country.

Old Mill Accountancy, which has offices in Exeter, Yeovil, Wells and Melksham, last night apologised after “human error” led to its mailing list being harvested from its website in July.

Many farmers who have created companies to carry out the cull often ensure personal details are not lodged on official documents in an attempt to prevent hunt saboteurs identifying where they live.