The Office of National Statistics (ONS) has confirmed that the UK 2011 census data has not been compromised, following reports earlier this week that a hacker group had stolen the information.

On Tuesday a post allegedly from hacker group LulzSec appeared on Pastebin and suggested that the group had accessed the 2011 census data. "We have blissfully obtained records of every single citizen who gave their records to the security-illiterate UK government for the 2011 census," the post read. "We’re keeping them under lock and key though… so don’t worry about your privacy (…until we finish re-formatting them for release)."

LulzSec denied it was responsible, pointing out that it always posts news of hacks on its Twitter feed first and that anyone can post content to Pastebin.

At the time the ONS said: "We are aware of the suggestion that census data has been accessed. We are working with our security advisers and contractors to establish whether there is any substance to this. At this stage we have no evidence to suggest that any such compromise has occurred."

Now however it has concluded its investigation and believes the incident was a hoax. Describing the allegation that it had been hacked as "without foundation," Census Director, Glen Watson added. "I can reassure the public that their census records are secure. We have strict measures in place protecting the nation’s census information. The claim that hackers got in looks like a hoax and our investigation concluded that there is no sign of any suspicious activity. The alleged hackers have also denied any involvement.

"However, we are not complacent and will remain vigilant. The security and confidentiality of census data remain our top priority," he added.

On Tuesday of this week police arrested a 19-year-old Essex man over alleged hacking attacks on businesses and government agencies across the world. Reports later emerged that the alleged hacker, Ryan Cleary, was arrested on suspicion of involvement with LulzSec.

Cleary is now facing five charges under the Computer Misuse Act 1990. His alleged crimes include an attack on the Serious Organised Crime Agency (SOCA) website.