A privately educated "city girl" who was leading a secret life as a high-class escort was bludgeoned to death with a pestle on her birthday by a banker in a cocaine-fuelled attack, a court heard.

Christina Abbotts was found dead in a bed in Crawley after failing to turn up for her own party in May.

The 29-year-old, who advertised her services under the name Tilly Pexton on Adultwork.com, had been hit 13 times on the back of the head with the black object - normally used with a mortar to crush ingredients - and possibly strangled, Lewes Crown Court heard on Tuesday.

The former Cirencester-based Royal Agricultural University student, who also went to Oxford Brookes, had been house-sitting at the top floor flat in Gossops Green for a friend who was away travelling.

Freelance consultant Zahid Naseem, who had been working for Toronto-Dominion Bank's London office, denies murdering Ms Abbotts some time between May 25 and 26, claiming the pair had a drug and drink-fuelled night together after which he woke to find her dead.

The 48-year-old stayed in the flat for 12 hours afterwards, sending pornographic pictures and videos to another sex worker and pretending to be unconscious when police broke down the door, prosecutor Christopher Tehrani told jurors.

He said: "He murdered Christina Abbotts.

"In short, the prosecution say the assault Christina Abbotts suffered which resulted in her death was brutal, savage, unnecessary and pointless.

"You will hear she had an active social life.

"Unknown to many of her friends and family, she was a sex worker.

"In some quarters she would be described as a high-class escort."

Naseem, who lives in Amersham, Buckinghamshire, with his estranged partner and two children, spent substantial amounts of his up to £250,000-a-year wage on sex workers, who he had used for about a decade.

He often took cocaine, drank a lot and used to frequent sex clubs as well as orgies and swinging parties, including The Vault, Killing Kittens, Heaven Circle, Cake Party and Club Anti-Christ, the court heard.

Wearing a dark suit, white shirt, burgundy tie and glasses, he sat quietly in the dock listening to the evidence in front of a public gallery packed with relatives and friends.

When interviewed, he told police he was "not some hyper, high-functioning psychopath" who was trying to concoct a story "a la Silence of the Lambs", adding: "I'm just telling you what happened or what didn't happen.

"I can't tell you more than that."

Ms Abbotts' family, from Stourbridge in the West Midlands, described her as a "sweet", "loving" IT worker who wanted to be an estate agent, and loved to travel.

Naseem told police he contacted Ms Abbotts after he was attracted to her pseudonym's profile describing her as a "privately educated city girl".

He was never violent but it was not uncommon for him to have memory lapses, he told police, and in messages on his phone he told one sex worker how he wanted to make her feel "degraded".

Naseem met Ms Abbotts on three occasions over six weeks in hotels and restaurants in London, after which he would pay her about £3,500 a time, describing their relationship as "commercial but very intimate", the court heard.

He also paid about £2,000 to the friend she was house-sitting for, and searched for her websites which rated her performance as a sex worker, telling another friend: "Luckily I'm here to protect her from harm and the sick perverts out there. I don't want to break her."

In messages to a work colleague who called her a "hooker", he responded: "How dare you. She's incredibly posh," the court heard.

On their last meeting the pair took a taxi from Amersham to Crawley, stopping at an Asda to buy alcohol before going to the flat, where she ordered cocaine, the court heard.

No-one heard from her after midday on May 25, which was very unusual, so friends called police and went in search of her when she did not turn up to her party in London.

When police broke down the door at about 2.30am the next morning, Naseem was found lying naked and motionless on the sofa with his eyes flickering.

He said the last thing he remembers was "passing out", but Mr Tehrani said: "The prosecution say there was nothing wrong with him. He was play acting."

Naseem insisted the pair did not fight and he had not hit her, but said when he realised she might be dead, instead of calling an ambulance, he went back to the living room, snorted four or five lines of cocaine and drank vodka - next remembering waking up in hospital.

When officers searched the property there was no sign of forced entry and Naseem's fingerprints were found in blood in the bathroom, the mortar - the other half of the pestle set - in the kitchen, and as well as a blood-stained bottle of Courvoisier brandy, cocaine and poppers were found.

The trial continues.