A man who described himself as a “monster” has been sentenced to life imprisonment after he strangled a young teacher and sexually assaulted her dead body.

Carl Langdell, 26, received the sentence at St Albans Crown Court today (June 3) for killing 23-year-old Katie Locke, from Buckhurst Hill, after going with her to a hotel room on Christmas Eve 2015.

Sentencing him, judge Andrew Bright QC said the minimum time Langdell must serve before being considered for parole is 25 years and 205 days.

He said: “I am firmly of the view that you pose a very great danger to women and young girls with whom you come into contact in the future, and I note that you have described yourself to others as a monster and a psychopath because of what you did to Katie Locke.

“Once you have served the minimum term I have set, it will be for others to decide when, if ever, it will be safe for you to be released.

“They will need to be guided by psychiatric opinion.”

He added he was “pessimistic” about whether psychiatric treatment could change Langdell’s emotionally unstable and psychopathic personality disorder, which made him a danger to women.

Ms Locke, a history teacher in Hackney, met Langdell on December 23 last year after speaking with him on dating website Plenty of Fish for about two weeks.

Langdell – who was doing a law conversion course – described himself on the site as a lawyer with his own firm.

Ann Evans, speaking for the prosecution said: “This is a lie.”

At the time of the killing, he was serving a suspended sentence for threatening to kill a girl and have sex with her dead body.

He had previously been detained under the Mental Health Act.

Langdell and Ms Locke had drinks in Shoreditch before taking a taxi to the Theobolds Park Hotel in Waltham Cross, where they checked in at 3.30am on December 24.

A receptionist said Langdell was “very intoxicated”, and he had been vomiting in the taxi.

As well as alcohol, he had cocaine, diazepam and medication for depression in his system.

Only Langdell knows precisely what happened in the hotel room, said Judge Bright QC.

The killer claimed they had intimate contact in the room.

He said he asked Ms Locke if she enjoyed BDSM, before putting his arm around her neck and strangling her.

After killing her, Langdell photographed and sexually assaulted her body.

Langdell wrapped her body in the room’s bedsheets before dumping her in a ditch outside.

There were abrasions and bruises around her body, and the prosecution said pathological evidence proved this happened before her death.

Mrs Evans said the injuries were not part of a sex game of any kind, and were the result of blows, an object or the floor.

At about midday on December 24, Langdell, of Roundmoor Drive, Cheshunt, admitted the “depraved” killing to a woman he had been dating.

He returned to his parents’ home in Cheshunt, and took the family dog for a walk.

While Langdell was out, Katie’s father William Locke turned up at his house.

Mr Locke and some of Katie’s friends had become concerned about her and had managed to trace Langdell online.

Langdell’s mother phoned her son and he said “I am a monster.

“I put her in the ground.”

Langdell was arrested by police in the Lea Valley Park, Cheshunt, and told an officer where he had put Ms Locke’s body.

Judge Bright QC said Ms Locke, a former pupil at Forest School in Snaresbrook, was a “thoroughly decent and innocent young woman who had done you no harm at all”.

He added Ms Locke, who taught at the Cardinal Pole School in Hackney and graduated from the University of Southampton, was greatly loved and missed by her family and friends.

Katie’s parents, William and Jennifer Locke, were in court yesterday and gave statements.

Mr Locke said: “The day she was born, it was like a new star had come to the sky.

“The day she was murdered, that star was extinguished.”

She was “loving, caring and thoughtful to everyone around her,” he added.

The family said: “Today’s result changes nothing, Katie is never coming home.

"All we can do is warn other young women to be careful in the hope that no other family ever has to go through the pain and trauma we have suffered."

Langdell pleaded guilty to killing Ms Locke on March 18.