LONDON, Aug. 27 (Xinhua) -- Prime Minister of the United Kingdom (UK) Keir Starmer on Tuesday vowed to "fix the foundations" of the country after "a decade of division and decline."

In a major speech delivered ahead of parliament's return from summer recess next week, Starmer highlighted the economic and societal "black holes" facing his government after 14 years of Conservative rule.

"We will do the hard work to root out 14 years of rot. Reverse a decade of decline. And fix the foundations," said the prime minister, who led the Labour Party to a landslide victory in the UK's general election last month.

Starmer was speaking from the 10 Downing Street garden.

A 22-billion-pound (29 billion U.S. dollars) black hole in the public finances "due to the last government's recklessness" had been discovered over the last few weeks, he announced.

The recent far-right riots rocking the country also revealed a societal black hole, he added, requiring the government to take action.

"These riots didn't happen in a vacuum. They exposed the state of our country, revealed a deeply unhealthy society, the cracks in our foundation laid bare, weakened by a decade of division and decline, infected by a spiral of populism, which fed off the cycles of failure of the last government," he said.

Starmer warned that the government's first Budget, to be announced at end of October, is "going to be painful," although he did not give details of what this would mean.

"We have no other choice given the situation we're in. So those with the broadest shoulders should bear the heavier burden," he said, adding that "things will get worse before they get better."

However, in a Q&A session following his speech, Starmer promised to stick to his general election campaign pledge not to increase income tax, value added tax or national insurance contributions for working people.

Former Prime Minister Rishi Sunak said on X that "Keir Starmer's speech today was the clearest indication of what Labour has been planning to do all along - raise your taxes."

Carla Denyer, co-leader of the Green Party, said on X, "Enduring more economic pain and hardship isn't what people voted for. They were told they were voting for change. Not voting for things to get worse before they get better. Labour needs to be honest about the fact that they could choose to make things better for everyone if they were bolder and braver."

However, Liberal Democrats leader Ed Davey supported Starmer, saying that "only the out-of-touch Conservative Party will deny the scale of the challenges" facing the government.

"From the millions stuck on NHS waiting lists to the millions struggling to make ends meet, the last Conservative government has left a toxic legacy. We need bold and ambitious action from the government to fix this mess," Davey said.