The policeman who failed to secure an injunction to prevent The Times revealing his identity had used his anonymous blog to offer advice on how to undermine police investigations as well as revealing confidential information about his cases.

Richard Horton, a detective constable with Lancashire Constabulary, began the NightJack blog in February last year.

At one stage he attracted nearly 500,000 readers a week with his pithy observations of life on the front line of policing. He was awarded an Orwell Prize for political writing in April this year.

The award judges were not aware that he was revealing confidential details about cases, some involving sex offences against children, that could be traced back to genuine prosecutions.

The detective has now deleted the website and received a written warning for misconduct for the fact that he was writing a blog, the success of which has led him to receive numerous offers to publish a book. His superiors are aware of the allegations that he was also revealing confidential information.

Some of the best-read sections of the blog were anecdotes about cases on which Mr Horton has worked. The people and the locations in the cases were anonymised, and some details subtly changed, but could easily traced back to real-life prosecutions.

One entry described the author investigating the rape of “Melissa”, a 14-year-old girl who was plied with alcohol and then raped in a hotel room. Mr Horton wrote that the offender had an Asian name, had hepatitis, and assaulted the girl at a seaside hotel, while filming it on his mobile phone.

A month earlier Ajmal Mohammad received an indefinite sentence at Preston Crown Court for raping a drunk teenager in a Blackpool hotel room. The court heard that he was infected with hepatitis C, and had filmed the attack on his phone.

Writing on the blog, Mr Horton revealed information that could have influenced the case, such as his suspicions that a key witness had misled police about her knowledge of the sex attack.

Another entry described an investigation against “David” a “local politician . . . with a seat on the council” who was found to have child abuse pictures on his computer. The blog said that “David” received a non-custodial sentence after a guilty plea.

In 2003 Bill Chadwick, a Preston councillor, pleaded guilty to possessing child pornography and was fined £1,000. But on the blog Mr Horton also revealed confidential details of other serious allegations against Mr Chadwick, which the Crown Prosecution Service decided not to pursue.

Other cases described on the blog can also be traced back to genuine prosecutions. In another entry entitled “A Survival Guide For Decent Folk”, Mr Horton offered advice to people who found themselves the subject of a police investigation.

His advice was to “complain about every officer... [and] show no respect to the legal system or anybody working in it”. Other observations included: "All you are trying to do by trying to explain is digging yourself further in. We call that a significant statement and we love it.”

When first confronted by The Times, Mr Horton refused to confirm or deny that he was the blog’s author, before trying to gain an injunction in the High Court preventing his name from being made public.

Lancashire Constabulary launched an investigation after being told that Mr Horton was the author.

A spokesman said: “The commentary in the blog is indeed the work of a serving Lancashire detective and clearly the views and opinions expressed are those of the author himself and not those of the wider Constabulary.

“We have conducted a full internal investigation and the officer accepts that parts of his public commentary have fallen short of the standards of professional behaviour we expect of our police officers.

“He has been spoken to regarding his professional behaviour and, in line with disciplinary procedures, has been issued with a written warning.”