LUXEMBOURG — A row over the European Union’s Lisbon Treaty threatened last night as Britain rejected French and German suggestions that Ireland could be left out of E.U. decision-making after voting against the treaty in a referendum.

Prime Minister Brown insisted yesterday that the British government would go ahead with parliamentary plans to ratify the treaty as E.U. foreign ministers meeting in Luxembourg agreed that last week’s Irish referendum defeat would not stop the Lisbon process.

But European leaders are struggling to present a united front after the Irish vote, with Paris and Berlin leading calls effectively to ignore the referendum result.

Ireland’s rejection threatens the treaty, which must be endorsed by all 27 E.U. members before it comes into force next year, creating a new E.U. president and foreign minister, and ending scores of national vetoes.

E.U. foreign ministers formally agreed to give the Irish government time to make suggestions about how to reconcile the country to the Lisbon Treaty.

But France and Germany are impatient to push ahead with the measures and hinted at moving on without Ireland.

In Berlin, the German foreign ministry said it was now possible that Ireland could be left out of some E.U. decisions.

Paris has dismayed Ireland by continuing to play down the significance of last Friday’s referendum vote.

The French Europe Minister, Jean-Pierre Jouyet, insisted that regardless of the Irish rejection, the European Union would be able to implement the treaty, including the selection of a president, after a delay.