"The long timeframe for the referendum also creates the potential for massive disruption in the working of the EU. We cannot have up to five years of EU summits and council meetings blocked or hamstrung by attempts to extort opt-outs and exemptions on the basis of this long-looming referendum."
Greens/EFA co-president Rebecca Harms added:
"Cameron wants the status of being in the EU and all the advantages of EU membership without any responsibilities: this cannot work. His vision of the EU as a free trade club is an outdated concept that is completely at odds with the challenges of the 21st Century. Europe's future depends on a common sense of responsibility."