GREEN MP Caroline Lucas revealed yesterday that she would join the board of the campaign to stay in the European Union.

Ms Lucas spoke a day ahead of the official launch of the campaign, which is to be led by Tory peer Lord Stuart Rose, a former chief executive of Marks and Spencer.

“I will make a truly progressive case for a more democratic and accountable European Union,” the former Green Party leader declared.

She has previously condemned the Brussels-based bloc’s pursuit of neoliberal austerity policies, slamming the “needless cruelty” of cuts and privatisations forced on Greece.

But she insisted that “a different kind of EU is possible — one where power is held locally whenever it can be, where citizens have a real say in decisions made in Brussels and where corporate lobbyists are banished from the halls of power.”

Trade Unionists Against the EU spokesman Brian Denny retorted that the EU was “designed to transfer power to unelected institutions and there are no mechanisms to return those powers within the EU treaties.

“Voters have to ask themselves how the campaign against corporate trade deals like TTIP is strengthened by acting as cheerleaders for the very organisations imposing them.”

David Cameron’s renegotiation of EU membership conditions will be conducted by the government rather than the In campaign — meaning that any changes will reflect Tory priorities such as accelerating TTIP and attacking the so-called social charter.

“Unfortunately, Caroline Lucas is deluded if she believes the fundamental treaties and institutions of the EU can all be rewritten and redesigned to serve the interests of the people rather than big business,” said Communist Party general secretary Robert Griffiths.

The EU’s most powerful bodies, the European Commission and European Central Bank, do not answer to any of Europe’s voters.

“The Common Market was a bosses’ club when it was founded in 1957 and is even more so now it is imposing austerity and privatisation across Europe,” said Mr Griffiths.

Other key figures in the In campaign include New Labour princeling Will Straw, son of former home and foreign secretary Jack Straw, who acts as the campaign’s chief executive.