Croatia were at the centre of a World Cup cover-up last night after Fifa admitted it had secretly let them off with a warning over fascist banners displayed by their fans.

The country’s march to the semi-finals - where they will face England tomorrow - had been notable for the apparent absence of any bigotry by their supporters, who brought shame on the nation at the last three major tournaments.

But the Daily Telegraph can reveal that, far from having cleaned up their act, Croatia fans have been at it again in Russia.

It can also be revealed that Fifa is fully aware of this but chose to keep quiet about it after controversially letting the Croatian Football Federation (HNS) off with a warning for the display of “political/discriminatory banners” by supporters.

The governing body, which claims to have a “zero tolerance” approach to racism, confirmed yesterday its disciplinary committee had sanctioned the HNS with a secret slap on the wrist following their Group D opener against Nigeria.

But it denied that amounted to a cover-up, stating that its regular announcements of disciplinary sanctions were focused on those “that resulted in fines”, and disclosing a secret warning had also been issued over homophobic chanting by Australia fans during their opening match against France.