The Green Party has pledged to fight for a "no" vote in the referendum on the European Union constitution.

As its annual conference in Weston-super-Mare drew to a close, the pro-environment party expressed its reservations about the current draft of the document.

The party said it was not opposed to a constitution in principle, but warned the current proposal "would entrench much of what's worst about the EU".

"We are committed to the European Union and to the idea of an EU constitutional treaty," said Green MEP Caroline Lucas.

"But we want a more progressive EU, an EU which serves social justice and provides for an ecologically sustainable future."

The party is also committed to joining the "no" campaign, where it is likely to work alongside the Conservatives.

However, the party said it would not back any "right wing or xenophobic arguments" against the constitution.

"The current proposals would commit the EU strongly to neoliberal economics, which would take Europe in the wrong direction," said economics spokesman Molly Scott Cato.

"Any move we might make towards building a sustainable economy could be ruled unconstitutional if it impeded the drive for profit that's central to the capitalist economy.

"There are more important things than profit."