Spiking is on the rise at house parties in the capital, with predators increasingly using drug-laced vapes to target victims, the Metropolitan Police has said.

Police chiefs say the “nature of spiking is changing” in London, with detectives seeing more cases involving over-the-counter and prescription medicines.

They also noted a rise in incidents taking place at house or flat parties, rather than at bars and nightclubs.

Detectives have also reported more cases involving THC-laced vapes, the main psychoactive chemical in cannabis, and the synthetic drug Spice, as well as high doses of everyday medicines such as antihistamines and travel-sickness tablets, which can cause drowsiness.

Detective Superintendent Dan Thompson, the Met’s spiking lead, said: “We’re seeing offenders use a wider range of substances than ever before, including everyday medications and substances added to vapes, while increasingly targeting victims in private settings such as homes, parties and student accommodation.

“Many of the substances now being used leave a narrow forensic window, which is why reporting as quickly as possible is so important.

“Reporting within the first 12 hours allows us to secure CCTV, obtain forensic evidence, identify witnesses and make arrests.”

More than 2,700 spiking-related offences were reported to the Met in the past year — 20% higher than the previous year.

But only 131 resulted in a charge, caution or summons, the force said.

More than half of victims were aged between 18 and 35.

It was previously reported by The Standard that offences were highest in Westminster, which covers the bulk of the West End, Lambeth and Camden.

The Mayor of London Sadiq Khan has pledged to crackdown on spiking in the capital, with the rollout of specialised vape-spiking detection equipment and the funding of specialised teams within the Met dedicated to evidence-gathering.

Night-time venues have also been incentivised to train staff to spot predatory behaviour, to introduce specially designed glassware to limit tampering, and to boost CCTV coverage.

But, Met Police say spiking cases can be difficult to investigate because drugs are rapidly metabolised.

The force also warned that self-testing kits sold online would not detect many prescription or over-the-counter medicines used to spike victims.

Victims are being urged to report suspected spiking as soon as possible, even if they have used a home testing kit and received a negative result.

Det Supt. Thompson added: “Nobody should hesitate to come forward. Even if some time has passed, we still want to hear from you.”

Two prolific sex offenders were jailed last year as part of separate Met investigations after they were convicted of targeting multiple women at their flats.

Rapist Chao Xu, 34, would give guests a drink he called “the spring of life”, that he had laced with substances including GHB and scopolamine, a travel sickness medication.

The Metropolitan Police said Xu had hidden cameras at his home in Greenwich, and had used them to secretly film women.

Xu has admitted offences against a total of 12 women spanning three years. But the Met has launched an appeal to find further victims, believing Xu’s offending may be much more widespread over the course of several years.

In a strikingly similar case, Chinese PhD student Zhenhao Zou, 29, also received a life sentence for drugging and raping 10 women in London and China.

He also amassed a grim collection of physical trophies taken from his victims, including clothing, jewellery, and a lipstick.

Spiking awareness events are taking place throughout Freshers’ Week at various universities across London.

By definition, spiking is when someone secretly adds alcohol, prescription drugs, or illegal drugs into another person's drink, food, or body without their knowledge or consent.