The toupee he had worn for over a decade was gone. He was nearly bald. Accompanied by three security guards, he would shuffle quickly into the dock, pale-faced, soberly dressed and appearing older than his 41 years.

At trial Port looked completely different from the toned blond escort of his online selfies.

Some mornings he would wave keenly at his legal team, breaking into a grin as he did so.

He never looked across at the families of the dead men.

In the witness box, he mumbled and was constantly asked to speak up, answered questions with evasive and unenlightening single word answers, and appeared blank and unaffected in the face of waves of distressing evidence.

When asked about videos of him having sex with an unconscious man, Port said they simply showed "the end of quite a few hours of normal sex".

Admitting lying to the police about the four deaths, he explained it by stating "the truth sounded like a lie, so I lied to make it sound like the truth".

In court, Port told even more implausible lies in order to explain his links to the dead men.

He painted a picture of the victims utterly divorced from reality - on the night of Kovari's death he was said to have attended a sex party with Whitworth. Port admitted writing the "suicide note" but claimed Whitworth dictated it to him. He alleged that Taylor, a sexually discreet non-drug user, took numerous drugs and suggested a two-hour sex session in the place where he was later found dead.

All this was nonsense. Port was, the prosecution said, a "habitual and compulsive liar."

DCI Tim Duffield, who led the successful investigation into Port, describes him as "one of the most dangerous individuals I've encountered".

"He's a voracious sexual predator who appears to have been fixated, nay obsessed, with surreptitiously drugging young, often vulnerable men for the exclusive purpose of rape. This is a highly devious, manipulative and self-obsessed individual."

Port had never shown any remorse.

There will be an inquiry into the original investigations. Seventeen Met Police officers are under formal investigation by the Independent Police Complaints Commission. Fifteen are understood to be from Barking and Dagenham.

Commander Stuart Cundy, from the Met's Homicide and Major Crime Command, acknowledges that Port could possibly have been stopped earlier: "The evidence we have heard at the trial of Stephen Port does identify that there were potentially missed opportunities."

John Pape thinks the failings in the investigation can only be explained by poor understanding of the lives of gay men, and even prejudice: "That maybe they thought: 'Oh that's what gay guys do'.

"I think if Barking and Dagenham Police had not taken the circumstances of those first three deaths at face value, if they'd questioned as a detective should do, if they'd empathised with the victims, then they would have connected them, and Stephen Port would not have been allowed to kill Jack Taylor."

Donna Taylor agrees: "It's awful because if they had done what they were supposed to and looked into things slightly different before, then Jack would still be here and maybe even possibly some of the other boys.

"It's obviously heart-wrenching for us as sisters, and obviously mum and dad, and obviously the other families. I don't think that at any point it was taken seriously. I really don't. And it's a life at the end of the day. Somebody's life."

Daniel Whitworth’s stepmother, Amanda Pearson, said in a victim impact statement: "We had a rich and fulfilling life ahead of us with Daniel, of that much I am sure, and it has been stolen from us. I cannot possibly describe the hole this has left us."

Anthony Walgate's friends are left only with memories.

"Anthony was a friend like no other, I doubt in this life I will ever meet anyone even a fraction like him," remembers Kiera Brennan.