The Times discovered that the author of the NightJack blog was Richard Horton, a detective constable with the Lancashire Constabulary.
Horton had attempted to stop The Times from revealing his identity and was granted a temporary injunction by a UK judge.
However, The Times fought back and was successful in lifting the injunction, allowing the newspaper to print his name and photo in today's edition.
The judge ruled that blogging was "essentially a public rather than a private activity".
The NightJack blog was started last February and won the Orwell prize for political writing in April this year.
It gave first-hand accounts of Horton's investigations and included strong social views and criticism of the policing system.
At its peak the blog was visited by 500,000 readers a week and known for its controversial entries. One advised readers to "complain about every officer and everything they do ... show no respect to the legal system or anybody working on it".
The blog also regularly criticised high-ranking ministers and provided detailed information about serious crimes and investigations, including sexual offences against children.
However, the Lancashire Constabulary said no action would be taken against Horton besides a written warning. Horton has since removed his blog and deleted all posts.
The ruling is significant for a multitude of bloggers who do not to reveal their names. They can no longer expect UK law to defend them against people who wish to expose their identity.
Hugh Tomlinson, Horton's barrister, said: "Thousands of regular bloggers who communicate nowadays via the internet under a cloak of anonymity would be horrified to think that the law would do nothing to protect their anonymity if someone carried out the necessary detective work and sought to unmask them."
Last week in the US, John Blevins was revealed as the anonymous leftist blogger Publius, who wrote scathing editorials of US domestic and international policy.
In 2006, The Sunday Times outed Zoe Margolis as Abby Lee, the pseudonym for the sex blog Girl with a One-Track Mind.