A prosecutor was not given information that Stephen Port was a suspected sex offender when he ruled out a homicide charge over the death of his first victim, an inquest has heard.

Anthony Walgate, a 23-year-old fashion student, was found dead outside Port’s flat in Barking, east London, on June 19 2014 after being given a fatal dose of GHB.

Port had alerted emergency services anonymously, claiming he was a passer-by, and then lied to police about the circumstances of Mr Walgate’s death.

Senior Crown Prosecutor Andrew Held was asked to advise on charging Port with the offence of perverting the course of justice.

Stephen Port murders
Anthony Walgate was Port’s first victim (Handout/PA)

He was handed a report by an officer in the case before agreeing with the proposed offence.

Henrietta Hill QC, for the victim’s family, presented to court a document on the charging advice given.

It stated: “The suspect cannot be charged with murder or manslaughter as there is no evidence that he killed the deceased.

“There is also no evidence that he administered a noxious substance.”

The witness confirmed that before issuing his advice he was given a police national computer (PNC) report that Port had no previous convictions.

But Mr Held said that to his knowledge he never saw a second PNC report detailing an allegation of non-consensual sex with a man.

Ms Hill said: “Does it follow that when you were considering Mr Port generally you did not understand anything about that previous arrest?”

The CPS solicitor replied: “I cannot recall.

“At the end of Port’s second interview there is a reference to his arrest. It may be I was not given details of that.”

Mr Held said he also did not have sight of a Police National Database (PND) report about British Transport Police concern that Port appeared to be in the company of a drugged man just days before Mr Walgate’s death.

The witness said there was a “very brief” reference to the incident in the Port interview.

Ms Hill observed: “You did not have anything other than what Port volunteered?”

Mr Held agreed he did not have information about what was on Port’s laptop either because it was submitted for examination after he gave his charging advice.

Earlier, a senior police officer expressed regret that he did not push harder for the investigation to be taken over by specialist homicide police.

On June 26 2014, Temporary Detective Chief Inspector Tony Kirk emailed senior colleagues saying the force had a duty to Mr Walgate’s friends and family to get to the bottom of what happened.

The borough CID commander wrote: “Anthony Walgate appears to be organised and experienced in his activities and has a group of friends who are obviously concerned at the manner in which he has died as, I am sure, so are his parents and family.

“I feel we as an organisation have a duty to his friends and family to get to the bottom of his death in what are increasingly suspicious circumstances.”

Mr Kirk’s lawyer, Richard Atchley, asked what he was hoping to achieve.

He replied: “I hoped the superintendent and MIT (murder investigation team) would accept my rationale and take on the investigation.”

He said that did not happen and none of the people he had emailed responded.

Mr Atchley asked: “Did you feel as acting DCI you were in a position to push it further at that time?”

Mr Kirk replied: “No.”

His lawyer continued: “With the benefit of hindsight, do you wish you had done so?”

The witness replied: “Yes.”

Mr Kirk told the court that staff had been “stressed” and “overworked”, with some reduced to tears, creating an atmosphere in which errors were made.

There were mistakes in sharing intelligence with colleagues about a previous allegation against Port, not instructing a search on the PND about him, and not sending his laptop off for scrutiny until nearly a year after he first struck, jurors have heard.

Mr Kirk had allocated an inspector to supervise the investigation but he stepped back “almost immediately”, the court was told.

Peter Skelton QC, for the Metropolitan Police, asked if he was disappointed by that.

Mr Kirk said: “Now knowing the outcomes, most definitely.”

Mr Skelton said: “Checking that actions were completed would be a basic fundamental part of its supervision. If that does not take place, errors are made.”

Mr Kirk agreed.

Mr Skelton said: “So far as the actions such as searching for PND intelligence or searching the laptop, do you have any answer why they were not completed? It appears to be human error.”

Mr Kirk said: “I do not know why they were not checked.”

Stephen Port murders
Stephen Port’s victims, (L to R), Daniel Whitworth, Jack Taylor, Anthony Walgate and Gabriel Kovari (Metropolitan Police/PA)

The court has heard that during his 16-month killing spree Port also gave fatal GHB doses to Gabriel Kovari, 22, Daniel Whitworth, 21, and Jack Taylor, 25, before he was caught.

Port, now 46, was handed a whole life prison term in 2016 upon conviction.

The inquests at Barking Town Hall are looking at whether police mistakes prevented Port from being stopped sooner.

Retired forensic scientist Denise Stanworth told jurors the level of GHB in Mr Walgate’s system was “off scale”.

It took more than a month for the preliminary results on samples of the victim’s urine and blood and a further four weeks for the final results.

Asked if there is a way to speed up the process, she said: “There is. The police can request the tests are carried out urgently. We have a fast-track service for which we charge quite a bit more.”

The final results identifying levels of GHB at more than 200 milligrams per litre were “off scale” and could provide a toxicological explanation for his death, Ms Stanworth said.

She also found high amounts of GHB in the body of Mr Whitworth but less than in Mr Walgate’s case.

Ms Stanworth told jurors that GHB is often hard to detect in the body because it breaks down quickly.

Ms Hill, for the victims’ families, asked: “Is it right that GHB had been known for being involved in date rape issues or incidents for quite some time?”

The witness agreed, saying incidents went back a number of years.

But she said she had only come across one case of GHB being used as a date rape drug and she had not been aware of it being used to kill someone.

She added that it is “quite a dangerous drug” with a fine tipping point.

The inquest was adjourned until Friday.