The paper stated that a package containing a letter with racist death threats and sinister powder were sent to Chelsea's training ground at Cobham on Tuesday.

"When you open this letter you will die a very slow and painful death," said the message, which also included threats to Grant's wife Tzofit.

Special Branch cops were called to the Chelsea training ground and investigation is still running, according to the police.

"There was panic at the training ground – the note said the powder would kill. Fortunately the substance turned out to be harmless," a Chelsea source was quoted as saying by the Sun.

"Avram got a lot of abuse at first, but that was from a tiny element and it had all but gone away.

"This is a very specific threat and a very threatening note which cannot be ignored.

"Specific actions are being put in place to ensure Mr. and Mrs. Grant are safe."