A senior Labour figure has warned Ed Miliband that "the entire Labour project could be jeopardised" if he failed to "recharge" the party's policies in key areas.
Former home secretary David Blunkett said the Opposition leader's TUC speech marked "a critical juncture in his leadership".
"This is Ed's chance to present himself as a relevant moderniser - and as a statesman willing to confront even the most difficult issues," he said.
"I support Ed and I admire the efforts he is making to drive the party into Downing Street.
"But, and I say this reluctantly, I fear those efforts will be in vain if he does not recharge our economic and foreign policies.
"There are just 20 months to go until the election - now is the time for him to display that courage and dynamism.
"If not, the entire Labour project could be jeopardised."