A coalition of five local authorities, Greenpeace and the mayor of London, Sadiq Khan, challenged those parts of the Airports NPS which state that there is a need for more airport capacity and a new north-west runway at Heathrow is the preferred option.
Objectors argued that the process leading up to the NPS's approval by Parliament - by a majority of 296 - was legally flawed and failed to take adequate account of the impact on air quality, climate change, noise and congestion.
The judicial review challenge was, however, robustly opposed by transport secretary, Chris Grayling, whose lawyers argued that the objectors' arguments were premature and trespassed on the on-going planning process.
Twenty-two grounds of challenge were pursued during a two-week hearing at the Royal Courts of Justice and, although six of them were found to be arguable, Lord Justice Hickinbottom and Mr Justice Holgate today dismissed all of them on their merits.
The court concluded: "We understand that these claims involve underlying issues upon which the parties – and, indeed, many members of the public – hold strong and sincere views.
"There was a tendency for the substance of parties’ positions to take more of a centre stage than perhaps it should have done, in a hearing that was concerned only with the legality, and not the merits, of the [NPS]."
The NPS, adopted in June last year, nominated a north-west runway at Heathrow - with a length of at least 3,500 metres and enabling at least 26,000 extra flights annually - as the government's preferred option.
Although the issue of whether development control consent should be granted for the runway has yet to be considered at a public examination, objectors argued that the NPS effectively ruled out other options - including a second runway at Gatwick or a differently configured third runway at Heathrow - which many believe are preferable on environmental and economic grounds.
Government lawyers earlier acknowledged that the NPS "clearly engages political, social and economic issues of the highest order", but pointed out that its adoption was the culmination of a six-year process, ending with Parliamentary approval by a large majority.
Bringing the challenge were the London boroughs of Hillingdon, Wandsworth, Richmond upon Thames and Hammersmith and Fulham, together with the Royal Borough of Windsor and Maidenhead, Greenpeace Limited, the mayor of London and lone campaigner, Neil Spurrier. Campaign groups Friends of the Earth and Plan B also put forward arguments in the case.
If they had succeeded in persuading judges that the NPS is unlawful and should be overturned, the expansion plans would have to be put to another parliamentary vote, extending yet again the marathon planning and environmental process of considering Heathrow's future.