Britain's main opposition Labour party on Thursday unveiled its general election manifesto, promising a radical agenda for social change, including nationalising key industries and a controversial second referendum on Brexit.

Party leader Jeremy Corbyn called it "the most radical and ambitious plan to transform our country in decades" and a "once-in-a-generation chance of real change".

Key pledges included the nationalisation of the rail, water, energy and broadband networks, in addition to huge investment in public services, corporate reforms and the introduction of a 32-hour working week. Labour has promised a "green industrial revolution" to tackle what Corbyn called "the climate emergency", by focusing new jobs and industries on efforts to tackle global warming.

But the most immediate problem is Brexit, with Britain due to leave the European Union on January 31 - just weeks after the December 12 poll.

Labour says that within six months of taking office, it will strike a new exit deal with the European Union and hold a second referendum on Britain's membership.

"The British people have the final say. Our government will carry it out, whatever the result of that vote is," Corbyn told an audience of party activists and media.

Opinion polls show Labour trailing Prime Minister Boris Johnson's Conservatives, and many activists admit that perceived ambiguity on Brexit is harming the party.

But Corbyn is hoping to galvanise voters like he did in the last election in 2017 by focusing on tackling inequality after nine years of Conservative austerity measures.

At the manifesto launch in Birmingham, central England, he said the programme was "full of popular policies that the political establishment has blocked for a generation".

He repeated the attacks on the rich and powerful that have been a feature of Labour's campaign so far, saying: "It's time for real change."

The manifesto includes big-ticket promises such as a five percent pay rise for public sector workers and the abolition of university tuition fees.

Corbyn said Labour would bring back into public ownership the "obvious monopolies", which includes parts of telecoms giant BT to provide free broadband for all.

The party envisages a huge increase in borrowing to fund investment, which the Institute for Fiscal Studies (IFS) think-tank had previously estimated at around £55 billion ($71 billion, 64 billion euros) a year.