The email addresses of more than 200 UK military staff have been leaked online.

Hacking group Anonymous is behind the leak, which in total consisted of thousands of email addresses belonging to UK residents, along with encrypted passwords. Many of these email addresses were for other intelligence and police officials, members of the Cabinet and also 242 members of staff for Nato.

Anonymous revealed on micro-blogging site Twitter on Christmas Day that it had got its hands on the information after gaining access to a US-based consultancy called Stratfor, which specialises in foreign affairs and security issues.

Anonymous is thought to have accessed a database of email addresses and passwords of 850,000 Stratfor subscribers. Around 75,000 credit card numbers and related addresses were also stolen, more than 400 of which are UK-based. More than 19,000 email addresses belonging to US military staff were also obtained by Anonymous and leaked online.

According to The Guardian, which got John Bumgarner, an expert in cyber-security at the US Cyber Consequences Unit, to analyse the leaked data, many of the email addresses are not usually publicly available. Furthermore, while the passwords are encrypted, it’s a code that can quickly be cracked using software readily available to the public.

"We are aware that subscriber details for the Stratfor website have been published in the public domain," said a government spokesman.

"At present, there is no indication of any threat to UK government systems. Advice and guidance on such threats is issued to government departments through the Government Computer Emergency Response Team."

Stratfor is in the processes of investigating the security breach and has subsequently taken down its website while this takes place.