Conor Benn's fight against Chris Eubank Jr in London this weekend has been "formally" postponed after Benn tested positive for a banned substance, co-promoters Matchroom and Wasserman Boxing announced on Thursday.

Eddie Hearn and Kalle Sauerland have conceded defeat in their attempts to stage the catchweight meeting at the O2 arena after the British Boxing Board of Control declared it was "prohibited" and "not in the interests of boxing".

The BBBofC issued its statement on Wednesday after it was revealed that trace amounts of the fertility drug clomiphene, which elevates testosterone levels in men, had shown up in a recent test by the Voluntary Anti-Doping Association (VADA).