Keir Starmer has told voters not to expect rapid public service improvements as he seeks to relaunch his faltering government with long-term targets on housebuilding, living standards, energy, policing, education and the NHS.

In interviews broadcast on Friday morning, the prime minister said he could not promise immediate change, blaming the previous Conservative government for leaving behind problems that could take years to solve.

With Labour trailing behind the Conservatives and Reform UK in some polls, Starmer said it could take a long time before British people saw the benefits of the decisions he was taking now.

He told ITV’s Good Morning Britain: “I’ve never said that can be done by Christmas.

“And I think that’s a deliberate decision of mine, because I think too many politicians have got in the warm bath, if you like, of saying everything’s fine, we’ll sort it all out, it’s already better. It’s not true. People don’t believe it and they’re fed up with being told that things are better when they’re not.”

Separately, he told the BBC: “You’ll have a better health service, you’ll have better houses, you’ll have better energy bills at the end of this and I’ll be judged, quite rightly, at the end of the parliamentary term whether I’ve delivered on what I said I would deliver on.”

Starmer announced his new targets during a speech on Thursday aimed at relaunching his government after a bruising first few months in power involving a series of unpopular decisions, including means-testing winter fuel payments and increasing national insurance and inheritance tax.

The prime minister told the BBC he did not plan to raise taxes again this parliament, but could not rule out doing so in any circumstance.

“I don’t want to suggest we’re going to keep coming back for more because that isn’t the plan,” he said. “What I can’t do, is say to you there are no circumstances unforeseen in the future that wouldn’t lead to any change at all.”

Starmer is gambling that voters will give him credit at the next election for delivering on his latest set of promises.

They are: to raise living standards, build 1.5m new homes over five years, ensure 92% of NHS patients wait no longer than 18 weeks for treatment, recruit 13,000 more police officers, make sure thee-quarters of children are ready for school at the age of five, and put the country on track for 95% clean power by 2030.

Starmer defended his decision not to include an immigration target, saying the Tories had failed to deliver on their own “arbitrary” targets while in power.

The prime minister was criticised for saying of the civil service: “Too many people in Whitehall are comfortable in the tepid bath of managed decline.”

Dave Penman, the general secretary of the FDA trade union for civil servants, accused the prime minister on Thursday of using “Trumpian language”. He told the BBC’s Newsnight: “I don’t think the prime minister understands how damaging his works have been. I talked to civil service leaders today about the challenges that they face, I think they feel a sense of betrayal.”

Matthew Pennycook, the housing minister, sought to defuse the row on Friday morning, telling LBC Radio: “We have to take the civil service with us on a journey to do government in a slightly different way … I haven’t experienced any particular civil servant in a tepid bath of declinism – they share our ambition.”