The family of a Kent chef murdered by a serial killer he met on Grindr has welcomed a documentary highlighting police failings that allowed him to continue targeting young gay men.

Stephen Port was jailed for life in November after being found guilty of drugging and murdering four men, including Daniel Whitworth from Gravesend, after meeting them on gay dating apps.

This week, a 50-minute documentary telling the story through the eyes of the families of three of Port's victims is due to be aired.

How Police Missed the Grindr Killer will be posted on BBC 3 on Thursday.

Between 2012 and 2015, Port, from Barking, attacked young men he met on Grindr, Fitlads, and other gay dating sites, killing four of them with drug overdoses in 15 months.

Port was convicted of the murders of Mr Whitworth, 21, as well as 22-year-old Gabriel Kovari, 23-year-old Anthony Walgate and 25-year-old Jack Taylor.

With each of the murders Port tried to cover his tracks, even by writing and planting a fake suicide note on Mr Whitworth framing him for the death of Mr Kovari.

The note said former Dartford Grammar pupil Mr Whitworth blamed himself for the death of Mr Kovari and could no longer live with the guilt.

Mandy Pearson, Mr Whitworth's stepmother, said: "We continue to seek answers and accountability from the police about how, for a whole year, they let us believe that Daniel had committed suicide, in which time Port had gone on to kill again.

"We all hope that the documentary will be a positive experience, resulting in further potential witnesses coming forward."

The documentary talks to the families of Mr Whitworth, Mr Walgate and Mr Taylor.

Mr Taylor's sisters, Donna and Jen Taylor, said: "Our family are grateful to the BBC for commissioning this documentary.

"It’s important that the Metropolitan Police Service understand that we will continue to highlight their failings until we get answers about their conduct and justice is done."

Sarah Sak, Mr Walgate’s mother, added: "It was harrowing to make this documentary because we had to relive the way we were treated by the police and the loss of our loved one all over again.

"However, we agreed with Daniel and Jack’s families that their stories must not be brushed under the carpet."

The Independent Police Complaints Commission is investigating the Metropolitan Police's handling of the four deaths after the investigation revealed widespread failings in Scotland Yard's approach to crime in the LGBT community.

It 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 is also investigating whether the force was "institutionally homophobic".

The Met is also re-examining 58 other drug-related deaths of young men in the wake of its failures in the Port case.

Solicitors for the families have renewed their appeal for anyone who had contact with Port to come forward and have reassured potential witnesses that they do not have to speak to the police.

Neil Hudgell of Hudgell Solicitors said: "We're currently gathering as much information as possible and would urge anyone who thinks they may have some relevant information, no matter how small, to contact us.

"It is crucial that we are able to build as full a picture as possible around Port’s activities, identifying any failings in the process and ultimately ensuring that lessons are learnt that will prevent the future suffering of innocent victims.

"There may be individuals out there who had contact with Port, either online or in person, or some may have been told information by another party which may be useful.

"We are fully aware of the trauma caused by Port to many individuals and we would like to reassure anyone with information that they will be treated sensitively and with respect.

"If a witness wishes to speak to the police, we will pass their details on. However, I am sure you can understand that given the circumstances some witnesses do not want to speak to the police and we will respect their wishes."

The legal team can be contacted on portenquiry@hudgellsolicitors.co.uk.