UNITE general secretary Sharon Graham challenged Sir Keir Starmer to decide “whose side he’s on” as she called for the nationalisation of energy.

She received a standing ovation as she addressed the Labour leader directly at the TUC Congress.

“Keir, our economy is broken, the people are suffering right now. This is the time to be bold — it’s not 1997, there’s no point grasping for a policy that’s stuck in the back of a 1990s sofa,” she said.

“You are watering down your own promises to give workers a real voice, she said, suggesting that unions should be more than “wads of money” and demonstrate their political power should Labour dilute its pledges on workers rights after winning a general election.

She said collective bargaining was the “tried and tested way” of boosting pay as she blasted the Tories for blaming unions’ fight for decent pay for inflation.

“We are not taking any lessons from the pied pipers of profiteering because it wasn’t wages that were driving up inflation, it was greedflation.

“Energy privatisation has failed pure and simple, it has crippled our communities and what remains of its public base. There’s only one credible answer, we need to take energy back into public house.”

Unite’s motion, seconded by the RMT, called on the TUC to recommit to a strategy of defending and extending collective bargaining as the primary way workers can challenge profiteering.

This included fair pay agreements being introduced through sectoral collective bargaining across the economy “as soon as possible in Labour’s first term.”

The union body is to also oppose any return to austerity and support “full public, democratic ownership of the energy network.”

It was passed unanimously. 

Unite said the “Big 4” energy providers have posted combined profits of £9.5 billion, up 84 per cent, with the profit margins of Britain’s largest companies soaring by 89 per cent since the pandemic.

Public ownership of energy could have saved the UK nearly £45bn in 2022, over £1,800 per household, with the cost of nationalisation of energy is equal to just two years of company profits at current levels, according to the union.

Sir Keir said: “The Labour Party and the trade unions have had a long relationship together and we had a big session at the beginning of the summer where we agreed policy going forward.

“So what you’ll see here is a lot of common ground as we go towards what we know will be really huge challenges.”