A section of Tottenham fans have responded to calls for them to end alleged anti-Semitic chants by singing "we sing what we want".
Peter Herbert, who chairs the Society of Black Lawyers (SBL), has said he will report chants to police if no action is taken by 20 November.
Some Spurs fans refer to themselves as the "Yid Army", a reference to the club's Jewish supporters.
Chants continued during Thursday's 3-1 Europa League win over Maribor.
Herbert said: "Why on earth do they think it is acceptable?"