Two London doctors are facing prosecution for allegedly carrying out illegal cosmetic surgery on women at clinics in the capital.

The women who had the “designer vagina” procedures were adults who paid for the surgery in the belief that it would make them more attractive.

But Scotland Yard detectives are now carrying out a criminal investigation after being alerted to the cases and deciding that the doctors’ actions involved a potential breach of legislation outlawing female genital mutilation.

Files on both doctors have now been submitted to the Crown Prosecution Service for charging decisions. A file has also been sent to prosecutors on a third case in Cheshire.

The news will raise hopes that a first conviction under anti-FGM legislation could be secured after the failure last year of the only prosecution so far.

The police investigations will also prompt renewed debate about cosmetic genital surgery, which includes labia reduction and vaginal tightening.

It comes after the pop star Sinitta revealed plans to have her own “vaginoplasty” filmed and broadcast online.

The singer, 53, has already put footage of a friend having a “designer vagina” operation on the Periscope site.

Such procedures — which critics say are wrongly promoted as enhancing sexual pleasure and attractiveness — are carried out widely at clinics in Harley Street and elsewhere.

The Home Office warned two years ago, however, in evidence to Parliament, that the operations may be illegal unless there was a medical or psychological reason for them.

That prompted renewed attention on the issue from police and prosecutors, resulting in the criminal investigation into the two London doctors.

It is understood that in both cases prosecutors believe the evidential test which they apply before bringing charges has been met.

Prosecutors are assessing whether bringing charges is in the public interest. Sources say that since the application of law to “designer vagina” surgery has not been tested in court, government departments are being consulted.

The views of royal medical colleges and anti-FGM campaign groups will also be considered as prosecutors prepare guidance to determine their approach. This is expected to be completed by the end of the year. Decisions over bringing charges will follow.

“So-called designer vagina surgery is classed as FGM when it comes to rules on mandatory reporting,” said a source. “The question [here] is whether it is in the public interest to prosecute.”

There are no official figures on the number of cosmetic genital operations carried out, since many are conducted privately, but doctors believe the surgery is becoming more common.

A study by the Royal College of Obstetricians and Gynaecologists has blamed the trend on “marketing by the private sector” and images online.

Doctors warn that women are being pressured by “unrealistic representations of vulval appearance in popular culture” and the advertising of the surgery as an “unproblematic lifestyle choice”.

A report by the British Society for Paediatric and Adolescent Gynaecology on labia reduction has warned that there is “no scientific evidence” to support the practice and that the health risks, particularly to girls under 18, include infection and a loss of sensitivity.

There are similar concerns about surgery designed to increase the size of the “g-spot” and tighten the vagina.

Campaign groups against FGM have complained that a “double standard” is applied under which ethnic minority communities, which have traditionally practised mutilation, are being targeted by law enforcers while identical surgery carried out on white women for cosmetic reasons is tolerated.

The Commons Home Affairs Committee raised the same concern in a 2014 report and asked Theresa May, then the home secretary, to consider whether legislation was needed to close this potential “loophole”. Mrs May replied that the 2003 Female Genital Mutilation Act covered cosmetic surgery.

In a submission to Parliament, she added: “The 2003 Act does not contain any exemption for cosmetic surgery. If a procedure ... is unnecessary for physical or mental health ... then it is an offence ... it would be for a court to decide if cosmetic surgery constitutes mutilation and is therefore illegal.”

The Crown Prosecution Service confirmed that it was assessing three files on suspected FGM offences, but declined to comment further.

The Met also declined to comment.