Mogelijk Turks lidmaatschap beïnvloedt Frans referendum EU-Grondwet (en)

A leading French polling organisation, BVA, has said that the issue of Turkey's membership of the EU could cause a 15 percent decline in the "yes" vote amongst centre-right voters in the forthcoming referendum on the European Constitution, according to French daily Liberation.

The 'Turkey issue' threatens to cause French President Jacques Chirac headaches as the campaign for the Constitution begins to gather momentum.

Many in his centre-right UMP party - including the President of the party and rival for the Presidential election in 2007, Nicolas Sarkozy - are in favour of the European Constitution, but sceptical about Turkey joining the EU.

And support for the Constitution appears to be falling slightly, according to polling organisations.

BVA said that the "yes" vote had declined by two points since the Socialists decided on a policy of supporting the Constitution. Another polling group - CSA - believes the decline in support is four percent.

The `yes' camp is still well ahead with roughly two-thirds of the vote. However, Mr Chirac will be mindful of the 1992 referendum on the Maastricht Treaty, during which support for the Treaty plunged dramatically in the run-up to the referendum. Despite a 30 percent lead at some points of the campaign, the "yes" vote received only 51 percent on polling day.

The exact date for the French vote on the Constitution has not yet been set, but it is expected in June.