The prospect of a big new source of gas on Europe’s doorstep looks strategically attractive when North Sea reserves are in decline and the region is fretting about its dependence on Russian supplies.

Yet development of eastern Mediterranean resources is far from straightforward because of the cocktail of political risks and rivalries involving the countries concerned.

“The exploitation of gas reserves could change dramatically the political and economic climate in the eastern Mediterranean,” said Emmanuel Karagiannis, an energy security specialist at King’s College London. “At the same time . . .[it] has the potential to exacerbate decades-old border disputes and generate new tensions.”