A judge has hit out at Cambridgeshire Police for continuing to employ a paedophile police officer even after he was caught photographing children eight years ago.

Nick Lidstone, 54, was sentenced to 14 and a half years in prison by Judge Anthony Bate at Norwich Crown Court after pleading guilty to 13 offences that included three counts of rape, three of indecency with a child, various sexual assualts and taking an indecent photograph of a child.

Judge Bate was incredulous that Lidstone had remained a police officer after being caught in 2005 taking "up-skirt" images of children with a spy pen in a Tesco.

He told Lidstone: "Why on earth you were not charged under the sexual offences act, I do not know.

"Whoever took that decision, it allowed you to carry on as a police officer."

Lidstone received a conditional discharge after pleading guilty to a public order offence, but because that is not a sexual offence his name was not places on the sex offenders' register. All of his most serious offences happened in the years afterwards.

Nick Lidstone (Cambridgeshire Police)

Cambridgeshire Police Chief Constable Simon Parr said: "At the time of the offences in 2005, the case was reviewed and the then Deputy Chief Constable decided Lidstone be placed on restricted duties.

"If we were faced with the same decision today, a more severe sanction would be imposed."

In 2005, as part of an agreement to continue working as a police officer, Lidstone began counselling.

The court heard that Lidstone had groomed his victim - who cannot be named for legal reasons - since she was nine years old, exposing himself to her, showing her pornography and taking indecent photographs.

One witness who knew the victim said her life had been "ruined" and that "she has never been able to integrate or make friends".

She did not make a statement to the court as she was so upset the thought of it "made her physically sick".

In pleading guilty, it was said that Lidstone has been "infatuated". He cried as details of his crimes were read out.

Deputy Chief Constable Alec Wood said: "The sentence handed out today reflects the horrendous nature of Lidstone’s crimes, which were committed over a prolonged period of time.