A residents’ group has asked a judge to rule that a council’s decision to approve a runway extension at Southampton International Airport was wrong.

Lawyers representing the Group Opposed to the Expansion of Southampton Airport (GOESA) say Eastleigh Borough Council acted unlawfully when it granted permission for a “164-metre development” to the north of the existing runway in June 2021.

They say residents were waiting for a Government decision on whether there would be a public inquiry into the plan.

Council and airport bosses disagree and say the claim should be dismissed.

Mr Justice Holgate is considering arguments at a High Court hearing in London due to end on Thursday.

A barrister leading the residents’ group’s legal team told the judge the council had agreed to the request not to issue a “decision notice” until there had been a planning inquiry decision.

David Wolfe QC argued, in a written case outline, that residents had a “legitimate expectation” that the council would not make a decision until then communities secretary Robert Jenrick had decided whether or not to “call in” the application for a runway extension.

He said the council’s decision was “procedurally and substantively legally flawed”.

Paul Stinchcombe QC, who is leading the council’s legal team, told the judge, in a written case outline, that “no such representation” had been made by the council and that the legitimate expectation argument failed on “the facts and the law”.

James Strachan QC, who is leading the airport’s legal team, said there was “no basis” for a suggestion that a “legitimate expectation” arose.

Solicitor Rowan Smith, who is based at law firm Leigh Day and represents GOESA, said outside court in a statement: “There is a real issue of local democracy at stake here.

“Our clients believe this should be properly examined by the High Court.”