Campaigners have lost the latest legal battle against possible expansion at Stansted Airport.

A High Court judge rejected their accusation that the key criteria being applied to decide on potential options for new runway sites in England were “infected by apparent bias”.

The Stop Stansted Expansion group had asked Mrs Justice Patterson, at the court in London, to order the Government-appointed Airports Commission, which was set up last year to address the issue of aviation expansion in the UK, to delay the publication of any options short-list until the criteria have been looked at again and consulted on.

SSE said there was apparent bias because of the conduct of Geoff Muirhead, a recently resigned member of the Commission.

Aviation expert Mr Muirhead is a former chief executive of Manchester Airports Group (MAG), the owner of Stansted since February. In September, he stepped down as one of the five commissioners appointed by the Commission after SSE warned Transport Secretary Patrick McLoughlin they would take legal action if he stayed.

SSE said he retired as MAG’s chief executive after 22 years with the group but was then immediately reappointed as “a highly paid ambassador to MAG, a role he continued to fulfil even after he was appointed to the Airports Commission”.

The court heard that MAG submitted proposals to the commission for a two-runway option at Stansted, and a four-runway hub airport option which would make Stansted the largest airport in the world.

The judge ruled that both Mr Muirhead and the commission might have acted in a way that was not “the most wise” and their conduct could have been regarded by a fair-minded observer as “less than ideal”. But the apparent bias accusation was not supported by the evidence.

In a statement following the ruling, SSE said it had achieved its principal objective in removing Mr Muirhead from the Commission, and wished to take time to reflect on the lengthy judgment before deciding whether to appeal the decision.

The judge ordered the group to pay the Commission’s legal costs of defending the proceedings, to be limited to £10,000.

MAG has submitted two proposals for Stansted expansion to the commission – one a two-runway option, and the second a four-runway hub airport which, the court heard, would make Stansted the largest airport in the world.