Children are being targeted by criminals to act as money mules, police have warned.

The scam involves transferring stolen money through children's bank accounts to hide it from the authorities.

According to The Times, the Met Police wrote to parents warning that pupils were being approached outside school gates and on social media.

Det Ch Insp Gary Miles said the Met wanted to "make parents aware so they can discuss this with their children".

In a statement, he added: "Children are getting accounts at a younger and younger age - 13-year-olds now have access to money that they didn't have before."

'Wads of cash'

According to fraud prevention service Cifas, the number of so-called "misuse of facility" frauds involving people under 21 has almost doubled in the last year.

It said there were 4,222 cases in the first half of 2017, compared to 2,143 in the same period last year.

Cifas' assistant director Sandra Peaston told the BBC: "Some of them are as young as 13 or 14, and essentially they're responding to adverts that they see on social media, on video sharing sites, which are offering money in exchange for moving money through their bank account.

"So they're being induced in by images of people waving wads of cash at them."

Cifas has previously reported that young people are increasingly tempted by fraudsters who offer a small cash fee in return for transferring money through their bank accounts.

Allowing a bank account to be used in this way carries a maximum sentence of 14 years in prison and could affect credit ratings, police said.

A force spokesman said: "The Met would always remind people not to allow anyone access to their bank accounts and that requests for money transfers should be declined unless you are certain you know where and from whom it has come."