• Former British doubles No 1 has same legal firm as PTPA

• The 33-year-old doubles star has always denied doping

The breakaway players’ union that is suing the tours and grand slam tournaments has thrown its weight behind Tara Moore’s $20m (£14.7m) legal battle against the Women’s Tennis Association in a new front in the sport’s civil war.

The Guardian has learned that Moore, the former British No 1 doubles player who this week brought a legal action for negligence against the WTA after being handed a four-year ban for doping, is using lawyers from the Professional Tennis Players Association’s (PTPA) legal partner, King & Spalding.