Sir Keir Starmer has launched a scathing attack on Suella Braverman over her recent controversial remarks on homelessness – warning Rishi Sunak that “without a serious home secretary… he cannot be a serious prime minister”.

Speaking during a debate on Tuesday’s King’s Speech, the Labour leader slammed her claims that living on the street was a “lifestyle choice”, instead calling it a “political choice” resulting from the scrapping of government housing targets and not enough new homes being built.

Politics live: Tories joke about Johnson and Truss as MPs debate King’s Speech

Sir Keir also appeared to reference other contentious comments by Ms Braverman, including her description of pro-Palestine protests at “hate marches”, saying using security issues as “a platform for her own ambitions” was making the job of the police even harder.

The prime minister failed to defend his home secretary during his response, even after being pressed further by Labour shadow minister Sir Chris Bryant, who asked whether he agreed with Ms Braverman on homelessness or whether she should be sacked.

Instead, Mr Sunak claimed the “actions” of the Conservative government had seen rough sleeping fall by a third and the Homelessness Reduction Act had helped “relieve or prevent” over 640,000 people from being homeless.

During the debate, Sir Keir criticised the King’s Speech as “a missed opportunity”, calling Mr Sunak’s pitch as the change candidate for the next election “ridiculous posturing”.

The Labour leader dubbed the government plans revealed by the King today as “more of the same sticking plaster politics”, adding: “Today we reach something of a new low because they’re not even pretending to govern anymore.

“They’ve given up on any sense of service. They see our country’s problems as something to be exploited, not solved.”

But the Labour leader saved his real ire for Ms Braverman and issued a warning to the prime minister over her recent controversies.

“We needed a King’s Speech that would draw a line under 13 years of Tory decline, a King’s Speech for national renewal and a serious plan for growth,” he said.

“But instead, we have a party so devoid of leadership, it is happy to follow a home secretary who describes homelessness as a lifestyle choice and believes that the job of protecting us all from extremists – the most basic job of government – is legitimate terrain for her divisive brand of politics.”

Read more: What exactly did Braverman say about homeless people?

Sir Keir added: “As director of public prosecutions, I worked closely with the police and counter-terrorism forces. Their job is hard enough already without the home secretary using it as a platform for her own ambitions.

“And so I say to the prime minister, think very carefully about what she is committing your government to do and think very carefully about the consequences of putting greater demands on public servants at the coalface of keeping us safe.

“Because without a serious home secretary, there can be no serious government and he cannot be a serious prime minister.”

Is Starmer preparing for Braverman as Tory leader?

Jon Craig

Chief political correspondent

@joncraig

Did we just witness a taste of the fierce Commons battles to come after the next general election?

The most blistering attack of Sir Keir Starmer’s speech in the debate on the King’s Speech was not directed at Rishi Sunak, but at Suella Braverman.

Plenty of MPs believe the home secretary’s controversial attacks on “hate marches” and rough sleepers making a “lifestyle choice” are all about playing to the Tory gallery ahead of a leadership campaign.

Some MPs even claim Ms Braverman is goading Mr Sunak into sacking her so she can launch a leadership bid before the general election.

So it’s highly significant the Labour leader launched such a harsh attack on the home secretary. Does he anticipate facing her across the despatch box if he wins the election?

Throughout Sir Keir’s attacks, Mr Sunak’s body language is highly revealing. He makes no eye contact with her and makes no attempt to shake his head during the onslaught.

And then, when the Labour MP Sir Chris Bryant joins the attack on Ms Braverman and challenges the PM to sack her if he disagrees with her “lifestyle choice” slur, he doesn’t even mention her and praises the veterans’ minister Johnnie Mercer instead.

So is she on borrowed time in the Cabinet ahead of launching a leadership bid? As soon as Mr Sunak finished his speech, she hurried out of the chamber.

Will she have relished Sir Keir’s attack on her? Almost certainly. And what about the lack of support for her from the PM? Good or bad news for her?

Probably bad news in the short-term, but probably not in the long-term, namely after the next election – when she no doubt hopes to be doing battle with Sir Keir across the despatch box.

While Mr Sunak did not have a response on the home secretary, who sat next to him throughout Sir Keir’s speech, he had lots to say about Labour’s plans for if they get into government.

He said the policies would lead to “higher inflation, more strikes, more immigration and higher borrowing”, and he said they would “give into inflation busting demands from their union paymasters”, calling such a move “dangerous”.

The prime minister also claimed Sir Keir “stands for the same old ideas”, while the government was “focused on the long-term decisions that will provide a better and brighter future for everyone”.

Read more: Will the pro-Palestinian march on Armistice Day go ahead?

Mr Sunak also trumpeted a number of his government policies announced in today’s speech, including:

• New licenses for gas and oil fields

• A new bill to phase out smoking

• Introducing whole-life orders for the most horrific murders

• A new legal framework to enable self-driving cars to be used on Britain’s roads.

“This King’s Speech builds on the strong foundation of economy well on its way to recovery,” added the prime minister. “It rejects big government and instead backs people and businesses to thrive.

“It strengthens society with historic measures to support the nation, health and education. It secures our streets and borders with tougher sentences for criminals and powers for police.

“And above all this, King’s Speech delivers change. Change in our economy. Change in our society. Change in our communities. It takes long-term decisions for a brighter future.”