Almost 200 drink spiking incidents have been reported to police forces across the UK over the past two months, the National Police Chiefs’ Council said on Friday.

The NPCC said there have been 198 confirmed reports of drink spiking in September and October across England, Scotland, Wales and Northern Ireland, plus 24 reports of some form of injection.

An earlier figure of 140 confirmed reports was revised after more data was received.

The number included both men and women, although the policing body said the majority of cases involved young women. Alleged offences have taken place at licensed premises and at private parties.

The 198 figure is based on data received from 40 police forces, and the NPCC said it is still to receive data from five forces which it expects over the weekend. It said 58 of the 198 reports of drink spiking were made to the Metropolitan police.

The NPCC lead for drugs, deputy chief constable Jason Harwin, said the reports were “very concerning”. He added: “We are working at pace with forces, law enforcement agencies such as the NCA [National Crime Agency] and other partners including the Home Office and universities to understand the scale of offending, establish any links between the allegations and ultimately bring any identified offenders to justice.”

Two men have been arrested on suspicion of conspiring to administer poison in connection with a spate of reported drink-spiking incidents involving needles in Nottingham.

Nottinghamshire police said the men, aged 18 and 19, were detained after it received information from a member of the public on Wednesday, after a general appeal for help.

The force said both had been arrested “on suspicion of conspiracy to administer poison with intent to injure, annoy or aggrieve” and placed in police custody. The arrests are not being linked to any specific allegation of spiking by a needle or contamination of a drink.

Both men have since been released under investigation, Nottinghamshire police said in an update. The force said it would deploy extra officers to ensure people can enjoy a “safe night out”.

There has been a surge in concern about drink spiking following a spate of social media reports from women who believe they may have been drugged via injection.

Earlier this week, the home secretary, Priti Patel, requested an urgent update from police on their investigations.

Meanwhile, groups from more than 60 universities across the UK have joined an online campaign calling for “Girls Night In” boycotts of nightclubs on 27 October to highlight the issue of women’s safety and put pressure on venue owners to tackle the problem.

As well as calls for covers for drinks, better training for night-life staff, and for police to conduct more rigorous searches of clubbers, campaigners also say there should be dedicated welfare staff within venues to help people get home safely.

A petition to legally require nightclubs to thoroughly search guests on entry has accrued more than 165,000 signatures.

With reported incidents in four university cities across Scotland, the University of St Andrews said it would introduce measures including random bag searches, safety patrols and testing of unattended drinks at student venues in a “zero-tolerance” approach to spiking.