Ireland will be offered additional guarantees of its sovereignty – possibly in areas such as taxation, military policy and family law – under an emergency plan to save the European Union’s Lisbon treaty, government ministers and EU officials said on Monday.

They said the plan, still in its early planning stages, would involve no changes to the treaty’s text, because all governments that have approved Lisbon would then have to ratify the altered document – a process regarded as virtually certain to fail, especially in the UK.