Britain's opposition Labour party vowed Thursday to overhaul the country after 13 troubled years of Conservative rule -- but insisted it would not spend its way out of trouble.

Jacket off and sleeves rolled up, Labour leader Keir Starmer delivered a new year's speech in the same east London venue as Prime Minister Rishi Sunak set out a limited list of priorities the day before.

"We booked it first!" Starmer told reporters, after Downing Street brought forward Sunak's speech in an apparent bid to upstage the Labour leader.

After 2022 saw the Conservatives ditch two prime ministers and ignite an economic crisis, Labour is riding high in the polls ahead of a general election likely next year.

Labour was ready for power, Starmer said, decrying Sunak's own speech for offering "commentary without solution" as Britons reel from a cost-of-living crisis and industrial action cripples hospitals and railways.

"More promises, more platitudes, no ambition to take us forward. No sense of what the country needs -– 13 years of nothing but sticking-plaster politics," he said.

Starmer's own speech was light on detail too, but set out a vision for a "decade of national renewal" at the start of a year that will see the coronation of King Charles III.

The Labour leader said he would transform the signature "take back control" Brexit slogan of former premier Boris Johnson into action with a new bill devolving powers from London to UK regions.

"I don't think anybody now seriously argues that this so-called oven-ready deal is actually working for anyone," Starmer said, ridiculing Johnson's trade pact with the European Union.

But Starmer again ruled out restoring Britain to the EU's single market, a key demand of businesses anxious to regain unfettered access to millions of customers and suppliers.

He said his party would bring about cheaper energy bills "forever" with a new public-private partnership on green power and end the strikes through dialogue with trade unions.

"But let me be clear –- none of this should be taken as code for Labour getting its big government chequebook out," Starmer stressed, seeking to pre-empt financial market concerns about a future centre-left government.

Conservative party chairman Nadhim Zahawi attacked Starmer's speech as "yet another desperate relaunch attempt".

"He should stop giving cliche-laden speeches and, instead, finally unveil a plan for people's priorities," he said.

On Wednesday, Sunak vowed economic growth, a halving of inflation, shorter hospital waiting lists, lower national debt and new legislation to stop boatloads of migrants crossing the Channel from France.