Gay serial killer and sexual predator Stephen Port is now being linked to another 58 drug-related deaths of young men.

The 41-year-old was today found guilty of murdering four men including Gravesend chef Daniel Whitworth, 21.

Outside court today Mr Whitworth's stepmother Mandy Pearson said: "We are emotionally and physically exhausted, and we are one step closer to making sure he will never have the opportunity to put another family through this again."

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Now, it's emerged detectives are re-examining dozens of deaths across London after the Port investigation revealed widespread failings in Scotland Yard's approach to crime in the LGBT community.

They revealed that 17 officers were being examined over their role in the case.

The inquiry into Port's victims only became a murder hunt after the fourth body, Jack Taylor, was discovered in October last year 15 months after the first killing, despite the similarities in each case.

Three of the bodies were found in the same churchyard within 400 yards of Port's home, including Mr Whitworth's. Each had a bottle of GHB on them and two were even discovered by the same dog-walker.

Port himself was arrested after the death of Anthony Walgate, in June 2015, and jailed for three months for perverting the course of justice after denying that he had ever met him.

Questions have also been raised by an LGBT group whether a "group think" among the officers stopped them from pursuing murder as a line of inquiry.

An investigation by the Independent Police Complaints Commission into the handling of the four deaths is looking at whether three of the victims could have been saved if the warning signs had been spotted in the first victim, Mr Walgate.

The IPCC will also investigate whether the force was "institutionally homophobic" in its handling of the case, as the Met admitted that a number of family members raised concerns about the lack of an initial murder investigation.

A forensics car used to investigate the scene of murders was only dispatched after two of the bodies - Mr Walgate and Mr Whitworth - were found.

Today Scotland Yard admitted there were "missed opportunities" to catch the killer.

And the Met also revealed that 17 officers have been given referral notices meaning their actions during the investigations were being examined - although none have been suspended or placed on restricted duties.

Commander Stuart Cundy, of the Met's Specialist Crime and Operations command, said: "The scale of this investigation has been one of the largest the Met has undertaken in recent years.

"The evidence at the trial suggests there were missed opportunities. It would be inappropriate to go into these during the IPCC investigation, but I acknowledge that there were missed opportunities and we are working with the IPCC.

"Jack Taylor was when it became a murder investigation. It was dealt with at a local level in Barking until then.

"A number of individuals raised concerns during the investigation, but that goes to the heart of the IPCC investigation."

He conceded knowledge of drug-related sex attacks and the gay "chemsex" scene in the force was limited, but said new guidance had been issued.

Video: Killer Stephen Port lies during police interview

Commander Cundy said: "It's fair to say the understanding and awareness of drug facilitated sexual assaults and chemsex amongst the frontline officers, and even senior investigators, was pretty patchy.

"But we are working with organisations such as Galop (an LGBT hate crime charity) and have issued new guidelines to officers to help with that awareness and understanding of the various drugs and issues of consent.

"When there is a homicide investigation officers will secure evidence and the IPCC investigation will go into if lives could have been saved or victims protected.

"I can't pre-empt what the IPPC investigation will find but whether officers were clearly looking at the suggested similarities of the four deaths will go to the heart of that investigation.

"Whatever learning and findings come out of that the Met will respond accordingly."

The Met's Forensic Services Directorate and the coroner's office are currently looking at another 58 deaths linked to GHB across the capital between June 2011 and October 2015.

Commander Cundy said: "We have launched a review with the coroner's office to look at drug related deaths to do with chemsex across London to see where we can identify GHB has been used in a death.

"This is a life-style choice for some people and the Met never condones the use of illegal drugs, but if you feel you have been a victim you must come forward as we will deal with that allegation of rape or sexual assault as a priority.

"The numbers of individuals reporting chemsex assaults is increasing year-on-year, the work we have done is about giving a much better response.

"One of the challenges is the life-span of the drug in the body. With GHB there is a fine line between the use for a sexual act, to unconsciousness, to death - that's the problem with this drug."

Port was first made a suspect when detectives saw him on CCTV meeting Mr Taylor at Barking train station in September 2015, and within three days "a body of evidence" against him was discovered.

Commander Cundy said: "When we examined these circumstances of these deaths the striking similarities between these deaths became clear there was foul play and that it might be the work of a serial killer."

More than 2,000 police exhibits, 10 million files of data and 20 social media accounts in a variety of names used by Port were analysed by investigators.

"Stephen Port is probably one of the most dangerous individuals I have ever encountered" - Detective Chief Inspector Tim Duffield

Detective Chief Inspector Tim Duffield, senior investigating officer in the case, urged any other victims of Port to come forward.

He said: "Stephen Port is probably one of the most dangerous individuals I have ever encountered.

"He is a voracious sexual predator who appears to have been fixed, nay obsessed, with drugging young men for his own sexual purposes and rape.

"He is a highly self-obsessed individual and through both criminal investigations he has never shown any remorse for his victims or their families. When he was arrested he tried to bluff his way out of trouble.

"We are working with the families of the victims and supporting those who have been victims of this horrific crime.

"Eight of the young men did not report crimes prior to police investigating Stephen Port.

"We are all very conscious there may be other victims of Stephen Port who have yet to come forward.

"I would urge victims who have been affected by this case to come forward. You will be dealt with confidentially.

"There is a lot of work on going to look at a number of GHB-related deaths across London but it is too early to say if they were as a result of foul play."

Although dating apps were a prominent feature of the Port trial, he said the majority of users are "completely safe".

Det Duffield said: "It's not simply an LGBT issue as it could have easily been a heterosexual killer. Social media platforms have made it really easy to pick up people anonymously.

"So we cannot single out Grindr as there were four different apps used to meet each victim and using these sites is not illegal and the majority of people are completely safe."

The Independent Advisory Group, set up in the wake of the Stephen Lawrence case and which also liaises with the police about LGBT issues, said the community gets different reactions depending on the borough a crime is reported.

Panel member Jack Gilbert said: "We are very pleased over 50 cases are being reviewed but there are broader inconsistencies of service the LGBT community receives across London.

"A trans person might get a different experience depending which borough they report to - this cannot happen.

"The police must address these borough disparities. I think senior management recognises there have been failures, they already admitted that.

"They must demonstrate a commitment to community engagement and enable the community to have a voice to change some of these processes so that these situations can be identified earlier.

"From our experience we feel it is highly likely to be some kind of group thinking on the part of some individuals, as 17 is a large number of officers.

"We can't say yet whether that has happened in this case yet but organisations can get into group thinking so as to shut off certain options in an investigation - such as murder in this case."

Although he welcomed the convictions, Mr Gilbert said the warning signs Port was a serial killer should have been spotted much earlier.

Police officers need to be better trained in recognising suspicious deaths relating to chemsex, he added.

Mr Gilbert said: "We hope this gives some closure to the families of the victims, and to the survivors. We recognise the hard work and professionalism of the homicide investigators.

"This has been a complex case with many victims. This case is not just about the LGBT community.

"Social media has made it very easy for people to meet up anonymously. This presents many challenges to personal safety, and creates the potential for much wrongdoing that an individual finds hard to report.

"The case involved a large number of victims of sexual assault culminating in the deaths of four people. This highlights the need for victims of sexual violence to have a safe channel to report their experience.

"We recognise that this involves very personal and sensitive issues, such as sexuality and drug use. We need to lower the barriers to allow people to report."

He said he "strongly supported" the decision by the Met to refer their handling of the four deaths to the IPCC, and welcomed the admission that "opportunities were missed".

But he added: "The police must demonstrate without delay a commitment to addressing any systemic or cultural issues that may have contributed to these sad events.

"There are clearly issues to be addressed about the handling of the four cases."

Mr Gilbert said: "These matters should be placed in the wider context of the consistency of the service that LGBT people experience from the MPS. It is our view that LGBT Londoners do not always receive service of the same equally high standard across all boroughs in London.

"We welcome other initiatives that will build trust and confidence for which we are taking a leading role.

"They are not linked to the homicides but are equally crucial. We have been assured that these will proceed without delay.

"They include, a revised guidance on chemsex, upon which we will be facilitating community input. A campaign to improve MPS organisational effectiveness in relation to LGBT-related hate incidents being developed by LGBT staff and community members."