A high-profile police unit that investigates sexual offences on the Tube and railways is set to be disbanded.

The specialist crime team was created by the British Transport Police to tackle unwanted sexual behaviour on public transport such as groping.

It had officers who actively searched for offenders on the capital’s transport network.

The move comes despite figures showing a huge rise in the number of crimes being reported.

Between last April and December there were 1,603 reports of sex offences on the Tube, trains and buses in London, compared with 1,117 for the period the previous year — an increase of 43.5 per cent.

Last month, Labour mayoral candidate Sadiq Khan urged the BTP to crack down on groping as a top priority.

The unit is being axed as part of a structural review by the BTP, which will also see the team handling assaults against Transport for London staff scrapped.

Two specialist crime teams will remain in London, covering theft of passengers’ property and bikes.

“These teams will be retained due to the high volume of these crime types and the limited investigative opportunities they offer,” an internal BTP document states.

There has been no official announcement but officers have been told the units are disbanding in the course of an employee consultation.

"Officers will be found alternative roles, or returned to uniformed posts. The document also revealed some staff may be made redundant.

A spokesperson said: “Under the new operating model, sexual offences will be investigated by any of the 269 officers dedicated to crime nationally.

"Our aim is to ensure that the significant expertise accrued by the existing dedicated sexual offence unit and our proactive teams is captured, and embedded as best practice across the whole new crime business structure at a national level.”

However, this appears to fly in the face of efforts to crack down on sex assaults in public spaces.

After a TfL survey revealed 15 per cent of women and girls had experienced unwanted sexual behaviour on the transport network, the BTP set up Project Guardian in 2013 with the Met, City of London police and TfL.

Created in conjunction with three women’s organisations, the End Violence Against Women Coalition (Evaw), Hollaback London and Everyday Sexism, it sought to encourage victims to come forward. Project Guardian has since been replaced with a well-publicised campaign, “Report it to stop it”.

None of the three women’s groups was aware the unit was being axed. Sarah Green, the director of Evaw, said: “We need to hear from BTP’s chief constable, and from the Department for Transport and the Home Office, as to whether such plans have been consulted on and what the intention is to ensure our national railways police force is able to respond to and ultimately to deter sexual offences.”

The spokesperson for the BTP, which is mostly funded by train operating companies, said: “Thankfully, the most serious sexual offences are rare on the railway and they will always be allocated a senior investigating officer supported by a dedicated team.”