A social worker accused of murdering a gay policeman before dismembering his body claimed his alleged victim wanted to explore "extreme fantasies" with him.

Stefano Brizzi, 50, is accused of fatally strangling 59-year-old Gordon Semple at his flat on April 1 during a drug-fuelled sex session.

The Old Bailey has been told Brizzi chopped up the body, before disposing of parts of it in the River Thames and trying to dissolve other bits in acid in his bathtub.

Crystal meth addict Brizzi was obsessed with US hit TV show Breaking Bad, in which the main character Walter White tries to dissolve the body of a rival in acid, jurors have been told.

PC Semple, originally from Inverness in Scotland, was reported missing by his partner Gary Meeks after failing to return to their home in Greenhithe, Kent.

Brizzi, an ex-Morgan Stanley web developer, was arrested on April 7 after neighbours complained of a "smell of death" coming from his flat.

Taking to the witness stand at the Old Bailey today, Brizzi denied he deliberately killed PC Semple.

Asked if he had ever been in trouble with the police before, Brizzi said: "No. I have never had any problem whatsoever with the law or any authority, like the police."

His defence barrister, Sallie Bennett-Jenkins QC, asked him: "Had you any intention of causing him real harm?"

Brizzi replied "None whatsoever."

Asked why the officer was in his flat, he said: "For the purpose of having fun. For the purpose of a sex encounter, a casual sex encounter, like many are taking place in London. It was a Friday night/afternoon."

His barrister asked: "And do you accept that you did act to dismember and to destroy his body?"

Brizzi said: "Yes, I did."

He invited PC Semple round to his flat to indulge in a drug-fuelled sex session in the afternoon, having spent a few hours looking for "fun" on Grindr, the court heard.

Brizzi said: "I had taken crystal meth, I had smoked, and as it appears, I was looking for fun since the previous night.

"Although it might appear weird, I was in a situation where I wasn't working and my daily schedule was not exactly regular.

"It was a Friday, and I decided I wanted to have fun, and have some chemsex."

PC Semple used the name 'Lee' during their encounter, as it was common to use a false name on Grindr, the court was told.

They both took crystal meth and GHB and had sex, and PC Semple later spotted his sex toys, Brizzi said.

He told the court: "He appeared to be very happy to be with me. He was making observations about the toys that he had seen.

"He liked the leather I was wearing. He started saying 'I really want to have fun with you'.

"At some point, he started to say, 'I want to explore some extreme fantasies with you'."

But they were both reticent about "the extent of our fantasies", he added.

They started inviting others on Grindr to come and join them for an orgy, while carrying on having sex, jurors were told.

He later hooded PC Semple and put a leash around his neck, the court heard.

Turning to Breaking Bad, Ms Bennett-Jenkins asked: "Were you a particular fan of it?"

Brizzi replied: "Well yes. I was a fan of many other TV series as well. It has been mentioned I like Heroes, House of Cards."

He said he was encouraged to watch TV series while recovering from his drug addiction.

Brizzi said: "They say in the first weeks of your recovery, your body is depleted.

"The only thing you really need to do is rest, sleep, eat. Let your body recharge, and literally do nothing.

"Sit on the sofa, start a TV series. Get addicted to chocolate, to sugar, to shopping.

"Substitute your dangerous addiction, try a much more tolerable one which is what I was trying to do."

The court also heard Brizzi was born in Tuscany to a devout Catholic family, had a brother and sister, and an uncle who was a priest.

He went to the University of Florence, and studied philosophy, Latin and the humanities.

Brizzi agreed he was "widely read", and was interested in comparative religions.

But he denied having read the Satanic Bible, which was found on his computer.

He said: "I never read that book. It was part of a series of downloads which I did in 2015. There are some very different materials in that downloaded material."

Brizzi said he realised he was gay aged 15, and that his family did not accept his sexuality living in Italy, which he described as "culturally speaking, a uniform country".

Brizzi added: "It was the 80s, and my family did not have the necessary understanding of homosexuality."

He found out he was HIV positive in 1993, and has been on medication ever since, jurors were told.

READ MORE: Gordon Semple 'did not die accidentally' during drug-fuelled sex game, court told

Brizzi became a web programmer in the 1980s, and later got a job in London as a web developer for the investment bank Morgan Stanley in 2012.

But he said he left in February 2015 after his addiction to crystal meth had spiralled out of control.

He lived off the "substantial amount of money" he had saved from working at the bank, he told the court.

Asked if he had tried to find work afterwards, Brizzi said: "It was problematic. I was already addicted to crystal meth, and this was ultimately the reason why I chose to resign from Morgan Stanley.

"I felt I didn't have the ability any more to carry on with my responsibilities."

He decided to cure his drug addiction before going back to work, Brizzi added.

The court was told Brizzi became addicted to crystal meth in 2013, after he was introduced to it through the chemsex scene - "an environment where people have a lot of casual sex encounters" and take drugs.

Questioned about how crystal meth made him feel, Brizzi said: "I was just extremely horny, very very sexually aroused. It was an instant sexual arousement.

"I kept using. And from that point onwards, I never stopped really."

Ms Bennett-Jenkins asked if he ever became violent on the drug.

But he replied: "No, I was becoming horny, very horny."

He tried to kick the habit but could not afford rehab, and joined a meditation group, before becoming a member of the Crystal Meth Anonymous group.

But he disagreed with the group's methods, which followed the 12 steps approach which referred to a belief in God, the court heard.

Jurors have been told Brizzi would tell the members intimate details about his sex life, and his belief in Satan.

Brizzi said: "I immediately found it a bit hard to fit in this kind of belief system as a way to address my addiction.

"For some reason crystal meth in London is almost exclusively used by gay men."

The group was made up of mainly gay men, and included former sex workers, he told the court.

Brizzi said: "It seemed to me rather odd that we had to not openly talk about our actual problems.

"I thought it wasn't really helpful. It seemed a bit fake to pray together, and not to mention our real problems, and that was my constant attitude towards the rest of the group."

Brizzi, of Southwark, south London, denies murder but admits obstructing a Coroner.

The trial continues.