One of England’s most senior police officers has apologised to the families of Stephen Port’s victims, as it emerged that a previous report highlighted a “serious failure of policing” in investigating a serial killer among London’s gay community.

Deputy Assistant Commissioner Stuart Cundy said he was “deeply sorry” there were a number of opportunities missed to arrest the drug-rape predator, saying it was “quite astonishing” that some officers did not follow instructions to get evidence in the case.

Mr Cundy was not in the Metropolitan Police Service (MPS) during Port’s 16-month killing spree in 2014 and 2015 but led the review of the investigations into the deaths of his victims, who were all young gay men in Barking, east London.

He highlighted five issues raised over the deaths of Anthony Walgate, Gabriel Kovari, Daniel Whitworth and Jack Taylor.

And he said things were “quite different now” within the police than during the period of Port’s offending.

Giving evidence on Friday at inquests examining whether the victims could have been saved if police had acted differently, Mr Cundy said: “Every single one of you absolutely had a right to expect a professional investigation to the standards all of us expected.

“It’s fair to say those standards weren’t met.”

Mr Cundy said there was a “clear possibility that Stephen Port could have been identified and arrested sooner than he was”.

He added: “I have never seen anything as unique and as having such terrible consequences as we’ve seen at this inquest.”

Inquest jurors heard that Mr Cundy’s review highlighted concerns over the quality of the initial investigations and the “professional curiosity” of those involved, as well as over police leadership, direction and support to officers.

He also raised concerns over the interactions between local policing and specialist crime investigators, the understanding of the use of the drug GHB – which Port fatally plied to his victims before dumping their bodies – and a lack of engagement with the LGBT+ community.

Addressing the victims’ loved ones, Mr Cundy said: “I can’t imagine putting myself in your shoes.

“I am deeply sorry – personally and on behalf of the MPS – that we didn’t conduct the initial investigations to the standard you expected and the standard you deserved.”

He said it was “a matter of personal disappointment” that things were not done as they should have been.

Mr Cundy added: “Please accept my sincerest apologies.”

The inquests previously heard accusations that police ignored intelligence, including from the victims’ family members and friends, that led to Port, and that the Metropolitan Police murder squad turned down requests from the borough officers to take over the investigations.

Mr Cundy said the family members “should not have been ignored”, and said officers were now better trained over LGBT+ issues.

The inquest jury also heard about a Met advisory group report from 2007, which highlighted a number of cases including that of the serial killer Colin Ireland, who tortured five gay men to death in 1993, which said the police investigation was hampered because they failed to identify links between the deaths.

Mr Cundy acknowledged there had been a lack of awareness about GHB in 2014, but said efforts had been made to better understand new and emerging drugs and usage patterns since Port.

The inquests also heard there were substantial delays in analysing evidence on Port’s laptop, which was seized after his initial arrest over Mr Walgate’s death.

He said the means of checking intelligence on a suspect was also “immeasurably different” now.

But he added: “When you hear things that didn’t happen when people have been told to do something, (it is) quite astonishing from my view that they weren’t done.”

The jury previously heard evidence that the local policing team was overworked as a result of cuts following the 2010 government spending review and did not have the specialist officers to investigate homicides.

Port, now 46, a former escort and bus depot chef, will die behind bars after being given a whole-life jail sentence for murdering Mr Walgate, 23, Mr Kovari, 22, Mr Whitworth, 21, and Mr Taylor, 25.

The inquests continue.