Care worker Stephen Nicholson has been jailed for life to serve a minimum of 33 years for the “execution-style” murder and rape of schoolgirl Lucy McHugh.

The 13-year old was stabbed to death in woodland at the Southampton Sports Centre on July 25 last year.

Sentencing Nicholson, the judge, Justice May, told him: “This was a pitiless attack on a child following months of sexual exploitation.

“The prosecution has described it as an execution and I am satisfied this is correct.

“The combination of his cold narcissism and hot anger dictated that she had to be put out of the way and he saw to it that this was done.”

Nicholson was convicted at Winchester Crown Court on Thursday of the murder of the 13-year-old, as well as three counts of rape when she was aged 12.

The trial heard that Nicholson, described by police as a “predatory paedophile”, had abused Lucy for more than a year while living as a lodger at her family home.

She had also said that she would tell her mother that Nicholson had got her pregnant although a post mortem examination showed that she was not pregnant at the time of her death.

William Mousley QC, prosecuting, described the murder as premeditated and a “execution-style” killing.

Detective Superintendent Paul Barton, of Hampshire police, said after the trial: “I would describe Nicholson as cold and calculated, I would describe him as a paedophile and I think he is someone who only thinks about himself and has taken full advantage of this family that have looked after him, provided a roof over his head.

“He has targeted Lucy, taken advantage of her and when she wanted a relationship with him, he has taken the decision to silence her once and for all by brutally killing her.”

The investigation into Lucy’s death, described by the CPS as “one of the largest in criminal history” was hampered when Nicholson refused to give police his Facebook password.

After applying through the US courts for access to his account, prosecutors only received a log of his Facebook contacts with Lucy but not the content of any messages. It finally arrived the day that the trial started.

The defendant, who admitted dealing cannabis, claimed he had not wanted to reveal his drug contacts via his Facebook account out of fear they would attack his family.

Nicholson, a tattoo artist, was convicted of targeting another girl aged 14 who he had sex with as a trade for giving her a cheaper tattoo.

The defendant denied having an appetite for sex with underage girls and said he did not have a relationship with Lucy.

He claimed Lucy had been “stalkerish” towards him and he had been at the home of an elderly friend when she was murdered.

Nicholson was linked to the murder through DNA evidence from both him and Lucy found on clothing, described by prosecutors as his “murder kit”, which was discarded in woodland in Tanner’s Brook, about a mile from the murder scene.

He also tried to cover his tracks by inflicting wounds on Lucy that could be interpreted as self-inflicted and also posed in different clothing on CCTV at a Tesco Express store.

The court heard that Nicholson, a father-of-one, had a love for reptiles and had a collection which included 12 pythons, chameleons, geckos and corn snakes.

Nicholson also told how he enjoyed “soft choking” women during sex which involved squeezing their neck to intensify the sexual effect.