A senior union leader has urged Labour to reconnect with workers because the party is now seen as being dominated by the political elite.
Labour needs to campaign on issues which relate to millions of people, such as jobs, pay and public services, said Paul Kenny, general secretary of the GMB.
He singled out shadow chancellor Ed Balls who was heckled at the TUC Congress earlier this month when he refused to join attacks on the public sector pay freeze.
Speaking before Labour's annual conference, which opens in Manchester on Sunday, Mr Kenny said he believes Mr Balls is under pressure to show that he connects with workers.
"You cannot talk about solving the problems of the economy by continually targeting some of the lowest paid people in the country. It is not feasible and we expect Ed Balls to stand up for the low paid. His speech will be a very important part of the conference for trade unions."
He said he hopes Mr Balls will not be subjected to a repeat of the heckling if he sticks to his line on pay, but "I would advise him against looking for a standing ovation".
A motion submitted by Unison for debate next week condemns the pay freeze for public sector workers. Unions will be pressing the party to start drawing up policies which will attract support at the next general election, including better rights for unions and scrapping employment measures such as having to pay to take cases to an employment tribunal, Mr Kenny said.
"I want to see the party be clear that worker access to justice is unfettered. Going to a tribunal should never be based on whether you can afford it."
Labour has become "unrepresentative", with a minority of MPs having any previous links with unions, said Mr Kenny whose union funds Labour to the tune of £2 million a year in affiliation fees and other spending.
"Everyone agrees it looks too much like a political elite. Working people have a lot to offer but most are put off by politics. Even good trade unionists don't engage with the Labour party."