GOVERNMENT plans for a huge airport at Cliffe have suffered a major setback after a High Court judge ruled ministers were wrong to exclude the expansion of Gatwick from its options for the South East.

Kent and Medway councils have welcomed the judgement, which follows a legal challenge the two authorities mounted against the Government. The judge effectively upheld all the grounds on which the two councils asked for a Judicial Review.

In a 50-page ruling, Mr Justice Maurice Kay supported the contention that because of the international environmental importance of Cliffe, it was irrational to exclude all reasonable alternatives. He ruled: "I have come to the conclusion that, in the context of these conservation considerations, it was irrational to exclude all Gatwick options from the consultation process."

The Cliffe site includes the Thames Estuary and Marshes Special Protection Area and the Northward Hill Site of Special Scientific Interest and National Nature Reserve. It is also a site designated as having exceptional value as wetlands of international importance, especially as a waterfowl habitat.

Cliffe is also protected through the Ramsar Convention on Wetlands of International Importance. On the general issue of whether it had been unfair to exclude Gatwick because of the need to consider all options for extra air capacity, the judge also backed KCC and Medway.

Council leaders were jubilant, claiming the ruling vindicated their decision to press for a judicial review. KCC Leader, Sandy Bruce-Lockhart, said "The judgement underlines the sanctity of international, European and nationally protected wildlife areas such as Cliffe."

A spokesman for the Department for Transport said: "The decision in the spring, not to propose another runway at Gatwick, was driven by our conclusion that it would be wrong to seek to overturn the legally binding agreement entered into by BAA, then in Government ownership, in August 1979. We will examine carefully what the judge has said. We have taken steps today to ensure we can appeal, if we wish to do so."

It is unclear at this point exactly what the repercussions of the ruling will be. One possibility is for the Government to agree to extend the current consultation period, which had been due to end this week.