Dating apps should do more to protect their users in light of the Stephen Port killings, police say. The 41-year-old chef murdered four young men he met via several gay dating apps, including Grindr and Gaydar, after luring them to his east London flat. He was also found guilty of a number of drug rapes.

His conviction on Wednesday (23 November) comes soon after the case of Stefano Brizzi, a former banker from Italy who killer a police officer, Gordon Semple, after meeting him on the Grindr app and luring him to his south-London flat.

The Met Police has been criticised for its handling of the investigation into Port after failing to spot a serial killer was on the loose until his fourth victim turned up dead in September 2015.

The force said it was re-examining 58 unexplained deaths in recent years involving the drug GHB.

Police say they are now working with charities to highlight the potential dangers of online dating.

Chief Constable Jane Sawyers, who leads on LGBT issues for the National Police Chiefs Council (NPCC), said while dating apps have a role in referring victims to police, "they could do more to prevent the offences in the first place".

She also said apps such as Grindr and Tinder could tell users to "get to know the person, not the profile" and warn of the dangers of fake accounts.

The use of dating apps by sexual predators is one of the National Crime Agency's (NCA) emerging threats to the general public, with early analysis showing its rising popularity in recent years had produced "a new type of sexual offender".

The most recent figures available show a six-fold increase in sex offences initiated by online dating between 2009 and 2014. The victims in 85% of these offences were female, just over 40% of whom were aged 20 to 29.

The last year for which figures are available, in 2014, there were 184 people who reported being sexually assaulted by someone they had met on a dating app or website, up from 33 in 2009.

The NCA said its analysis showed there are twice as many cases of internet dating sexual offences compared to bogus taxi driver sexual offences.

Port was a prolific user of gay dating apps, using false names and fake profile pictures on some of his profiles to trick his victims into trusting him.

Simon Bailey, the Norfolk chief constable, and the national police lead on violence and protection, said those who use online dating should be "as security-conscious as possible".

"If you are planning on meeting someone for the first time, take precautions and meet in a public place," he told the Guardian. "Individuals should stop all communication with anyone who attempts to pressurise them into something they are not comfortable with. If this happens you should contact the dating app provider immediately to discuss your concerns and always report any criminal activity to the police."