Local authorities which campaigned against the Heathrow expansion are seeking legal advice as to whether they can appeal the High Court's Decision.

On May 1 the court ruled in favour of dismissing the legal challenge brought by four London councils.

There is no automatic right of appeal and permission to appeal is needed, in the first instance, from the court which heard the original legal challenge.

An application for permission to appeal the ruling was due to be submitted to the court yesterday (May 9) by the coalition of councils - supported by Greenpeace and the London mayor.

The application for permission to appeal is based on two specific grounds which are both have their origin in European Law.

The first ground relates to the Habitats Directive which is designed to preserve protected species and the second concerns the relationship of the Airports National Policy Statement to the councils' Local Plans also the noise assessment and metric used by the government, both of which fall under the umbrella of the Strategic Environmental Assessment Directive.

In considering whether to grant permission to appeal, the Court will have to determine whether there is a realistic prospect of an appeal succeeding.

If the Court refuses the application, there is a right to make a further application for permission to appeal directly to the Court of Appeal which will also have to consider whether an appeal has a realistic prospect of succeeding.