Chelsea will defend themselves against charges of failing to control their staff when a two-day FA hearing into the so-called “Battle of Stamford Bridge” begins today.

The club will deny that Sam Bethell, their groundsman, used racially insulting language towards Patrice Evra, the Manchester United left back, as the visiting team’s substitutes warmed down on the pitch after the Barclays Premier League match between the teams in April.

Chelsea could be found guilty of failing to control their staff even if the more sinister allegations are proved unfounded, as there is photographic evidence of Bethell tangling with Evra in a flare-up that was witnessed by dozens of onlookers, but they are determined to clear their employee of the smear of racism as a matter of principle.

Evra has already gone on record as saying that he did not hear any racist comments, while Chelsea will also allege that United changed their version of events three times. United are expected to allege that Evra was called a “f***ing immigrant” by Bethell, with Mike Phelan, their assistant manager, believed to be the source of the complaint. Evra is expected to be cross-examined today.

The FA originally brought a case against Bethell but, at a preliminary hearing in September, an independent commission ruled that the FA did not have disciplinary jurisdiction over him because of the wording of his contract. The FA instead charged the club with failing to ensure that he conducted himself in an orderly fashion. Chelsea have also been charged with failing to include the necessary provisions in Bethell’s contract.