A paedophile who admitted attempting to groom a young girl for sex by using the internet to make contact has been jailed indefinitely.
Peter Warren, 48, of Rushmere Road, Ipswich, sent sexually explicit emails to a newspaper reporter he believed to be a 12-year-old girl called Charlotte.
Middlesex Guildhall Crown Court heard they included pornographic images.
The judge on Friday set a minimum tariff of two years before Warren can apply for parole.
The court heard Warren came into contact with the News of the World journalist in an internet chat room in March 2005.
They met in a park in east London in May last year.
Prosecutor Peter Zinner told the court the reporter alerted police who set up a surveillance operation.
Officers arrested Warren as he sat in East Ham Park chatting to a reporter who he believed to be the young girl he had been communicating with.
Mr Zinner said: "There was never going to be a meeting with a child. It was going to be a meeting with an undercover reporter.
"But in the defendant's mind it was a meeting with a child with the intention of sexual activity."
The reporter also posed as a 13-year-old girl with the sign-on name Ruth12b and was again contacted by Warren who sent the girl he believed to be Ruth pornographic pictures and engaged in sexually explicit talk.
The court heard that Warren had never had sex before and was of previous good character.
Judge Worsley rejected claims by defence barrister Samantha Leigh that Warren would never have had the capacity to act on the suggestions he made over the internet.
He said he was satisfied that Warren was of "serious risk to the public".
The judge said he disagreed with submissions that because no child pornography was found in a search of Warren's computer and there was no evidence of any previous attempt to contact children for sexual reasons, that the man did not pose a risk to young children.
He disqualified Warren from working with children and ordered him to register on the Sexual Offenders' Register for life.