Five Premier League clubs are facing the threat of being hit with a transfer ban as part of Fifa’s investigation into the signing of foreign players under the age of 18.

Chelsea are one of the clubs and a report by French investigative website Mediapart has claimed that Fifa’s Integrity and Compliance unit have internally proposed a two-year transfer ban on the London club stretching across four windows.

Mediapart are one of the organisations publishing documents obtained by Football Leaks. Other than releasing a short statement in which they insisted they are cooperating with Fifa, Chelsea would not comment on the report or the case.

But sources close to the Fifa investigation have told Telegraph Sport that Chelsea are not the only Premier League club facing the possibility of a transfer ban. “This a massive investigation that will implicate a number of clubs," said the source. "It will touch most of the big clubs around Europe and in the Premier League.”

It is believed at least four other Premier League clubs are under investigation and some of the biggest clubs in Europe are also being looked into.

A Fifa spokesman said: "As communicated in September 2017, investigations were opened concerning the club Chelsea FC as well as other English clubs in relation to potential breaches of the Regulations on the Status and Transfer of Players. The proceedings are ongoing and, to date, no decision has been passed by the Fifa judicial bodies. Thus, the clubs are to be presumed innocent unless decided otherwise. No further information can be provided as the cases are ongoing. Any update will be communicated in due course."