An appeal by 12 British plane spotters convicted of spying in Greece could bring a "positive development", the Greek Prime Minister has said.

Costas Simitis's words seemed to offer hope to the spotters, who had said they were not hopeful of clearing their names and feared having to serve out their jail sentences.

It was not clear whether he was suggesting their convictions would be overturned or simply seeking to dispel fears that their appeal could be delayed until next year.

Yesterday, after meeting Prime Minister Tony Blair, he said: "I think there will be a positive development but in our system it is for the courts to decide."

His words were given a cautious welcome by the spotters, including Chris Wilson, 46, of Erica Way, Horsham, and those campaigning on their behalf, who earlier held their own news conference to set out their grounds for appeal.

The 12 and two Dutchmen were arrested in Kalamata in southern Greece last November and held for more than six weeks until being released on bail.