In her first public comments since Thursday’s elections, Rayner called for Sir Keir to take more action to tackle inequality and “squeezed living standards”.
“We are in danger of becoming a party of the well-off, not working people,” she added.
“What we are doing isn’t working, and it needs to change. This may be our last chance.”
In her 1,000 word statement, she called for Labour to offer regional mayors more economic powers, raise the minimum wage, and be “unafraid to promote new forms of public, community and cooperative ownership across the board”.
It comes after Labour lost almost 1,500 councillors in England, mainly to Reform UK and the Greens, and was kicked out of power in Wales.
Labour came joint second in Scotland, where the SNP retained control of the Parliament.
