Alleged serial killer Stephen Port has told jurors he wrote a suicide note for a former Dartford schoolboy he is accused of murdering in exchange for sex.

The 41-year-old chef allegedly planted the note in the hand of 21-year-old Daniel Whitworth taking the blame for the death of 22-year-old Gabriel Kovari, from Lewisham, three weeks earlier.

Both young men died from an overdose of date rape drug GHB and were found by a dog walker dumped in the grounds of Barking Abbey churchyard, just 400 metres from Port's flat.

The prosecution say Port wrote a fake suicide note as part of an elaborate cover-up to get away with murdering the men at his home.

Giving evidence at the Old Bailey, Port told jurors he knew them separately but had nothing to do with either of their drugs deaths.

He told jurors he had gone to a "sex and drugs party" in Ilford with Mr Kovari, who went home early with a man called "Dan".

It was only later that he realised that Dan was the same man he had met online and arranged to meet in Barking weeks later in September 2014.

Port said Mr Whitworth had become upset and confessed to him he had gone with Mr Kovari to the churchyard to have sex and when he woke up, he was dead.

The defendant told jurors: "He said they took some more G (GHB), snorted some more lines of meph. They had sex behind a tree in a dark corner of the churchyard, it's private.

"He was not sure what happened next but they sat down next to a wall and passed out for a couple of hours.

"He said when he woke, Gabriel was sleeping on his shoulder. He went to make him wake up and his head dropped into his lap. He said he tried to raise him, tried to bring him round but he couldn't. He looked like he stopped breathing.

"He tried to give him mouth to mouth but he could not rouse him. He leaned him up against a wall. He said he panicked. He was going to call an ambulance but did not know what to do, so he left him."

Afterwards, Port said Mr Whitworth became "angry at himself" and worried he would be caught by his DNA.

He said: "I explained to him he did not need to worry because it was not being treated as a murder. I said he should go to police, I would go with him and explain what happened."

Port said the young man suggested they "have some fun first", meaning sex and drugs.

Later, the defendant said Mr Whitworth, from Gravesend, became upset again and asked him to write something for him on a piece of paper to get it "off his chest".

Port said he stuck to taking down his dictation but added in a line saying "BTW please do not blame the guy I was with last night" after joking that he might get the blame himself.

The defendant told jurors: "I thought it was just the G talking and he was just getting his emotions out of his system.

"I didn't believe he was actually going to do it. I would have stopped him. I would have done anything to prevent him doing it."

Asked by his lawyer David Etherington QC why he wrote the note for Mr Whitworth, Port said: "Just because he asked me to. He said 'if you do this for me, I will let you f*** me afterwards'."

Port denies 29 offences against 12 men - including four murders, seven rapes, four sex assaults and administering a substance with intent.

The trial continues.