Tony Blair will say that “nothing less than ‘born again’ head-to-toe renewal will do” for Labour, as party members prepare to choose their next leader.
The ex-PM – who led Labour from 1994 to 2007 – will warn the party could be out of government for a decade unless it adopts a new “radical” politics.
Rebecca Long-Bailey, Lisa Nandy and Sir Keir Starmer are competing to succeed Jeremy Corbyn as Labour leader.
The results of the contest will be announced on 4 April.
During the campaign Mr Blair has faced some criticism from leadership hopeful Ms Nandy, who argued that under his leadership, Labour “tacitly accepted that four decades of economic conservatism was a bigger priority than people”.
In a speech marking the 120th anniversary of the founding of Labour, Mr Blair is expected to acknowledge that his advice is not “particularly welcome to today’s party”.
“But then it occurred to me that there are only two people born in the last 120 years who have actually won an election for Labour – and alas Harold Wilson is long gone,” he will add, referring to the Labour prime minister of the 1960s and 70s.
He will warn the Conservatives could be in power for ten years unless Labour adopts a new “radical” form of politics.
“The problem is that we have defined radical politics by a policy agenda which is hopelessly out of date, with ‘moderate’ politics being just a milder version of it,” he is expected to say.
“We must redefine what radical means. We’re living through a technology revolution which is the 21st century equivalent of the 19th century Industrial Revolution.
“It will change everything and therefore everything should change including radical reorientation of government.
“This is the context in which we tackle inequality, promote social justice and redistribute power.”