Brussels, June 19 (Reuters): Triumph over the EU’s adoption of a landmark constitution gave way to gloom today as leaders of the 25-nation bloc returned home fuming with each other and split over who to select as European Commission chief.

The accord on a new set of rules for a Union of 450 million citizens that now straddles the old Iron Curtain was a welcome relief for leaders who suffered a wave of public apathy and Euroscepticism in last week’s European Parliament elections.

“Today is great day for Europe,” declared former French President Valery Giscard d’Estaing — who chaired the convention that drew up the text of the constitution — after a deal was clinched yesterday at the end of a two-day Brussels summit.

But the risk of rejection by any one of several member states due to hold referendums could still sink the EU charter, whose aim is to make the bloc’s institutions less complex, less remote and easier for citizens to understand. British Prime Minister Tony Blair hailed the treaty as a good deal for Britain after he won a successful rearguard battle to preserve national vetoes on key policy areas. But he now faces an uphill task winning a referendum on the constitution probably late next year.