The European Union’s efforts to limit the damage from Ireland’s rejection of a landmark EU reform treaty ran into trouble on Friday when the Czech Republic refused to give an explicit promise to approve the document.

At an EU summit in Brussels, the fall-out from the Irish vote spread to other policy areas as Nicolas Sarkozy and Angela Merkel, the French and German leaders, ruled out EU membership for applicant countries in south-eastern Europe unless the Lisbon treaty came into force.