Anti-Semitic death threats have been sent to Avram Grant, the Israeli manager of Chelsea Football Club, in a package containing a white powder. Death threats have also been made against his wife, Tzofit.

A police source confirmed that a note addressed to Grant, 52, claimed that the powder was lethal and had stated: “You are a back-stabbing Jewish b******. When you open this letter you will die a very slow and painful death.”

The club’s training ground at Cobham, Surrey, was sealed off yesterday after a member of staff opened the package. It later turned out to be harmless.

It was disclosed yesterday that, since becoming manager last September, Grant has been sent dozens of anti-Semitic e-mails and letters from people claiming to be Chelsea fans.

Denis MacShane, a former Labour minister and author of a recent study into anti-Semitism, told The Times that he had received dozens of hate-filled e-mails, which had been copied to an e-mail address purporting to be Grant’s. They had also been copied to Roman Abramovich, the club’s billionaire Russian owner, who is also Jewish.

A club source confirmed that Grant had received hate-mail.

One message, sent to Mr MacShane, Grant and Mr Abramovich, said: “I have been a Chelsea supporter since 1968. And Chelsea has always been a White, English, Christian football club in the land of St George. I would rather see Chelsea playing in the Isthmian league, than see you Jewish b******* ruin it with Russian, American and nasty Israeli terrorist Jews.”

A far-Right presence is long known to have existed among Chelsea supporters in previous decades, although this was believed to have been diminishing in recent years. Mr MacShane said that the e-mail campaign appeared to show there was still a problem within football, and not simply within a fringe band of extremists outside.

“I have been absolutely horrified at e-mails I, and other MPs, have received of a hideous anti-Jewish nature since Mr Grant has become Chelsea manager,” said Mr MacShane, who is now a backbencher after serving as Europe Minister under Tony Blair.

“I believe that the time may have come to launch a parallel movement to kick anti-Semitism out of football, as well as the general Kick Racism out of Football campaign, which has been very successful. Reports of continuing racist chants from Chelsea fans, as well as those at clubs like West Ham, are evidence that anti-Semitism still exists within football stadiums.”

He added: “We must not brush this under the carpet by saying it is just an outside problem.”

Chelsea would not make any official comment. But a club source indicated that Grant, who is a former manager of the Israeli national team, had received items of mail, saying: “I would refer you to the statement of Bruce Buck last year, saying that he had received some. Those comments stand.”

In October Mr Buck, the club chairman, said of the fans’ messages to Mr Grant: “We welcome all constructive points of view. But there have been a few which could be viewed as racist and anti-Semitic and that must stop immediately. This is one thing we will not tolerate, whether in written correspondence, on the chat pages, on posters or banners, or through singing and chanting. It unfairly smears the reputation of the vast majority of the Chelsea fans.”

A spokesman for Surrey Police said: “We were called to Chelsea’s training ground at Cobham at 12.15pm yesterday after they received a suspicious package. A white powder contained within the package was analysed by specialists from Surrey Fire Service and was determined to be a harmless substance. Detectives are continuing investigations.”

When the package was received, Grant and Chelsea were in Athens before Tuesday night’s Champions League 0-0 draw with Olympiakos.

Prosecutions for racist offences in England and Wales rose by nearly a quarter to 7,694 last year, Crown Prosecution Service figures show. But there was a drop of more than 37 per cent in prosecutions for religiously motivated offences.