A deal between Greece and Albania that aimed to settle a longstanding disagreement between the two countries over their sea borders and continental shelf rights could be scuppered by a legal challenge being mounted by opposition parties in Tirana, it emerged yesterday.

The agreement, signed in April by then Prime Minister Costas Karamanlis and his counterpart Sali Berisha, was due to be ratified by the country’s parliament on Monday.

However, Socialist opposition leader Edi Rama says the deal, which enforces a clear delineation in the Ionian Sea, lacks transparency and damages Albania’s sovereignty. Six parties are due to file an appeal with the country’s Constitutional Court to stop the accord being approved.

The Socialists’ campaign is seen as part of a wider effort to challenge Berisha’s government, which the opposition claims won June’s parliamentary elections thanks to voting irregularities.