In spite of having a partnership agreement with USDAW in the UK, Tesco has refused to even talk to the UFCW, which has 1.3 million members in supermarkets across the USA.

Tesco has so far launched 60 Fresh & Easy food stores with plans for hundreds more across California, Arizona and Nevada.

Mr Obama urged Tesco to meet the UFCW in a letter to Tesco chief executive Sir Terry Leahy. The Senator wants Tesco to discuss a "principles of partnership" agreement with the UFCW.

"Ensuring that workers are able to exercise their rights to organise" will be an important element of his campaign for the presidency, reports the Financial Times.
A growing number of unions have backed the Obama campaign - with the Senator raising labour issues and promising to take a more sceptical stance on free trade.

"Dialogue has to be the way forward and we hope Senator Obama's welcome initiative can break the deadlock at Fresh & Easy" said Philip J. Jennings, General Secretary of UNI Global Union, speaking on behalf of the recently launched UNI Tesco Global Union Alliance.

"European companies should not adopt double standards on labour issues when they go overseas"