London - Controversial British world heavyweight champion Tyson Fury is suing UK Anti-Doping (UKAD) over allegations he failed a doping test last year, according to a statement released on Tuesday.
The Sunday Mirror reported on June 26 that Fury - who won the heavyweight title in an upset defeat of Wladimir Klitschko last November - had returned a sample with a banned steroid in it.
The newspaper claimed that nandrolone - which aids muscle growth - had been discovered in a test Fury underwent in February 2015, well before his remarkable win over the ageing Klitschko.
Fury, 27, categorically denied the allegations at the time, while his legal team said the results of tests from March and May last year were contradictory.
According to the Mirror, Fury's cousin Hughie, also a boxer, failed a test for the same substance, although he too denied any wrongdoing.
The legal team for the two fighters said they had issued proceedings to the High Court.
"The two boxers strenuously deny taking any performance-enhancing drugs," their lawyer Lewis Power said in a statement.
"However, during the last five weeks, leaks about these charges have appeared in the press and both boxers have been the targets of continual abusive language on Twitter."
An interim judgment is expected before Fury makes the first defence of his WBO, WBA and IBO heavyweight titles in an October rematch against the 40-year-old Klitschko.
The bout was due to take place in Manchester on July 9 but Fury pulled out after failing to recover from an ankle injury.