West Ham United could face serious disciplinary charges from the Football Association after their fans were heard airing anti-Semitic chants at their Tottenham Hotspur counterparts.
A section of Hammers supporters appeared to make hissing noises - mimicking the gassing of Jews in the Holocaust - while Spurs followers also claimed Adolf Hitler chants were sung by the travelling fans on Sunday.
Tottenham's Jewish following has been worn as a badge of honour by the club the past 30 years as the club have embraced their Yids moniker. However this has led to anti-Semitism on the terraces.
Reference was also made to the attack on Tottenham fans in Rome earlier this week in which two were stabbed by Roma ultras despite playing Lazio in the Europa League.
“Can we stab you every week”, “viva-Lazio” and “there’s only one Paolo di Canio” were all audible in the London derby.
Di Canio, a cult figure at Upton Park who played for the club between 1999 and 2003, is a self-confessed Fascist and used to play for Lazio.
West Ham manager Sam Allardyce and his opposite number André Villas-Boas both refused to comment on the singing.
Allardyce said he "didn't hear" the chants as he was "concentrating" on the game and refused to become a "political animal" by passing judgement.
"It is the least of my worries," the 58-year-old added.
Villas-Boas meanwhile was reluctant to "mar the performance" after Tottenham ran out 3-1 winners, delivering what many observers claimed was their best performance of the campaign.
Ironically Spurs have recently emerged as the target of the Society of Black Lawyers' chairman Peter Herbert's campaign to stop them from chanting the word 'Yid' on grounds of anti-Semitism.
The club defended their supporters and instead suggested it would be more constructive to ban chants akin to those sung at White Hart Lane at the weekend.
UPDATE: West Ham have released a statement...
West Ham United are in contact with Tottenham Hotspur to assist them with their investigation into the conduct of a small number of supporters and alleged inappropriate chanting during yesterday's match at White Hart Lane.
West Ham United will take the strongest possible action against any of their supporters, including enforcing life bans from the club, that are found guilty of behaviour which is categorically not condoned by West Ham United.
During the 46 games in the Championship last season, West Ham United had zero arrests for racism or violence, so while we are surprised to see such reports today, we will examine any available evidence of such conduct thoroughly and take the appropriate action.