Oxford United have suffered a new setback in their plans to build a new stadium after a legal challenge was launched in the High Court.The Championship strugglers’ proposed 16,000-seater venue on land known as the Triangle was given planning permission last year.The Triangle will be a 3,500-seat upgrade from the Kassam StadiumAFL Architects / Oxford UnitedThe U’s chairman, Grant Ferguson, has described the new stadium as a ‘once-in-a-generation opportunity’.Oxford United CEO Tim Williams had previously warned that the future of the club was at stake if planning permission was denied.That is because there is a ticking clock on their future at Kassam Stadium, which has been Oxford’s home since 2001.The 12,500-capacity ground, which has only three stands, was named by talkSPORT’s Adrian Durham as one of the worst in the 92.Former Oxford United owner Firoz Kassam, for whom the current stadium is named, sold the club in 2006 but has still retained the stadium ownership through his company, Firoka Group.The football club have a tenancy agreement with the real estate venture, which expires in 2028 with no scope for an extension.Oxford United new stadium updateIn October, Oxford United’s planned solution to build a new stadium was approved by Cherwell District Council and the government.However, campaign group Friends of Stratfield Brake (FoSB) lodged a judicial review challenge in the High Court last week.Campaigners are concerned over the new stadium’s impact on the local environment and transport, and also claimed that Cherwell District Council acted unlawfully when approving the plans.Oxford United extended their unbeaten run at the Kassam Stadium to five matches with a win over WatfordGettyWhy has a legal challenge been launched?A spokesperson for FoSB said: “We have engaged with the council throughout this process and made our concerns clear at every stage, including through formal legal correspondence.“Unfortunately, those concerns have not been addressed, leaving us with no option but to bring this judicial review.“We believe the decision is flawed and that the impacts of this development on the adjacent woodland and transport have not been properly considered.”Development of Oxford’s new stadium includes a hotel, restaurant and gym to surround land known as the Triangle, near Kidlington.Leigh Day partner Ricardo Gama, whose law firm is representing FoSB, said: “Our clients felt they had no choice but to file court proceedings because the council has failed to address their concerns over the impact which the stadium development would have on an ecologically important woodland and on local traffic.“They look forward to putting their arguments to a judge.”Oxford United have a deadline set on leaving their current stadiumGettyA spokesperson for Cherwell District Council added: “The council is confident in its decision and in the event of any judicial review will robustly defend its position.”Oxford United, meanwhile, are currently already in a battle on the pitch to avoid relegation from the Championship.As it stands, just seven points separate teams sitting from 19th spot to 23rd in the second-division table.Oxford United, in 22nd, can leapfrog West Brom with a victory at Derby, with the Baggies also facing a potential points deduction.