Tortoise first reported that a female Labour MP claimed she had been sexually assaulted by a male shadow minister.

The BBC has been told she reported the incident to the Met Police and the Labour whips.

Labour said the whips had urged her to make a formal complaint to the party.

However, Tortoise reported that she "felt his popularity within the party would stand against her".

In response to the report, the Metropolitan Police told the BBC they received a report in March that a woman was sexually assaulted by a man in London in July 2021.

The incident is alleged to have happened after a summer party in London.

The force said: "At the victim's request, the incident will not now be investigated at this time."

It added that enquiries were at an "assessment stage" and a formal investigation had not been launched.

The Met has not identified either MP.

Labour told the BBC they had not been contacted by the Met, nor received a formal complaint.

A party spokesman said: "We take any allegations of this sort very seriously and would always encourage individuals to go to the parliamentary process, the Labour Party process or the police.

"In terms of the Labour Party process, it is a thorough, robust and independent process that individuals can have confidence in."