Chelsea chairman Bruce Buck revealed that the London club will not accept any kind of 'anti-Semitic' abuse against Israeli manager Avram Grant. The majority of Blues fans questioned the recent appointment of the unfashionable Grant at the expense of fans favorite Jose Mourinho. However, the Chelsea chairman described some of the comments made by the fans towards the new coach as totally unacceptable. "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," Buck said. "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. "And it unfairly smears the reputation of the vast majority of Chelsea fans who rightly do not want to be associated with such activity." Grant's start with Chelsea featured a 2-0 defeat at Manchester United, followed by a disappointing goalless draw with Fulham last weekend. The Israeli manager will face another tricky task when his side visit Spanish giants Valencia in the UEFA Champions League clash on Wednesday.