Tesco has refused to sign an agreement forcing it to stick to its corporate social responsibility pledges in the US, telling pressure groups it will be judged instead by its actions instead.

Tesco, whose Fresh & Easy business goes operational on the West Coast this autumn, has been making great play across the Atlantic of its green and worker-friendly policies.

But the publication of a report by Occidental College criticising its labour and environmental practices has raised concerns that its statements of intent are nothing but rhetoric.

The Alliance for Healthy & Responsible Grocery Stores - made up of 25 groups including political, religious and union bodies - has now asked Tesco to sign a legally binding Community Benefits Agreement, formalising its commitments on fair wages, affordable health benefits and reduction of greenhouse gases.

“Many companies have made a song and dance about being a great employer and a steward of the environment, but then we see little action,” said Elliott Petty, retail policy analyst for one of Alliance’s member groups. “The community is wary - and weary - of corporations that make hollow promises, so we want Tesco to make a formal commitment.”

Tesco, however, has refused to sign. “When we open our stores everyone will be able to decide whether we lived up to our promises,” said a spokesman.