Two people have been arrested by Met detectives over the genital mutilation of a baby girl less than two months old, the Standard has learned.

The alleged perpetrators and their victim, under- stood to have been five to six weeks old when the “cutting” was done, all live in Britain. Police hope the arrests could lead to a landmark first British prosecution for female genital mutilation.

Sources say the victim’s age is unprecedented and extensive efforts are being made to gather the evidence needed to bring charges. The barbaric practice — which can involve the removal of all or parts of the labia and clitoris or the sewing up of the vagina — has been illegal in Britain since 1985.

No charges have been brought since then as secrecy and a lack of reporting have hindered police efforts to enforce the law.

Detectives believe evidence about the mutilation of the baby girl could now lead to a breakthrough and have submitted a file to prosecutors. But because the surgery was carried out overseas they are still unsure whether charges can be brought.

The reason is that under legislation passed in 2003, making it a crime to take or send a girl abroad for genital mutilation, either the victim or the alleged offenders must be UK citizens or permanently resident here.

In the baby’s case, it is understood that although she is now a British national it is unclear whether she was when mutilated. Also the two alleged perpetrators were not permanently resident here at the time.

Medical records are being sought to determine when the alleged crime took place. If it was after the girl got her UK passport, a prosecution is expected to be approved.

The new Director of Public Prosecutions, Alison Saunders, said just days ago that a first prosecution for FGM could come “relatively shortly”, with at least one case offering a “possibility” of charges.

Those comments are thought to relate to the case of an older victim.

That means a first criminal charge for FGM could still be imminent even if legal problems block a prosecution in the baby girl’s case.