One of the US’s largest unions this week came to the UK to confront Tesco.

The United Food and Commercial Workers Union (UFCW) argues that Tesco’s alleged anti-union stance in the US and perceived refusal to engage with local communities is jeopardising its chances of success stateside.

UFCW campaign director Emily Stewart said: “They are not successful in the States right now. We don’t see these stores catching on. Not at this point. They are making it much harder for themselves.”

She added: “There are demonstrations in front of stores because they don’t engage communities. We could play a role helping them to do that.”

She spoke as the 1.3 million- strong UFCW brought its “The Two Faces of Tesco” campaign to this country on Wednesday. It aims to highlight how Tesco’s close relationship with UK union USDAW has not been replicated in the US with the launch of the grocer’s Fresh & Easy format.

The campaign has been backed by likely winner of the Democratic presidential nomination Barack Obama.

Writing to Fresh & Easy chief executive Tim Mason, Obama said “co-operation with community leaders” was the right way for Tesco to do business in the US. He acknowledged Tesco’s “bold promises to create quality jobs, provide environmental leadership and develop stores in neglected communities”, but said: “These concerns would be better eased by working with a coalition like Los Angeles’ Alliance for Healthy and Responsible Grocery Stores.”

In a letter to Sir Terry Leahy, Obama’s rival Hillary Clinton also urged the Tesco chief executive to “provide the leadership needed for your company to sit down with labour representatives”.

No comment was available from Tesco.