Sir Keir Starmer’s speech pledging to smash the “class ceiling” by boosting poorer children’s education was interrupted by protesters accusing him of U-turning on green policy.

Two young people who had been part of the backdrop to the Labour leader’s address in Gillingham pulled out a banner and heckled him for watering down his climate ambition.

The activists with the Green New Deal Rising group urged him not to scale down plans to borrow £28 billion a year to invest in green jobs and industry.

Sir Keir asked them to “let me finish” and said he would speak to them after his speech before they were led off the stage by security.

He was setting out his reforms if he wins the next election to set a goal of half a million more children reaching their early learning targets by 2030 as he expands on the party’s intention to improve teaching for the under-fives.

Sir Keir hopes a Labour administration will be able to make state schools as good as their elite private counterparts.

“I promise you this, whatever the obstacles to opportunity, wherever the barriers to hope, my Labour government will tear them down,” Sir Keir said.

“We will change Britain, break the link between where you start in life and where you end up.

“The earnings of our children should not be determined by those of their parents.”

If you're going to use young people as props you should be interested to hear what they have to say

But the protesters interrupted him to say they want a “green new deal right now”.

Green New Deal Rising said the two protesters were students who had been invited by the party to stand behind the leader as he spoke.

Fatima Ibrahim, co-director of the campaign, told the PA news agency: “If you’re going to use young people as props you should be interested to hear what they have to say.”

She said the group will “escalate” their tactics leading up to the Labour conference in the autumn.

“A core part of what we’ve asked is for Rachel Reeves and Keir Starmer to meet with us. If we don’t hear back we’ll be forced to escalation.”

She said Labour represented an “opportunity to start a conversation” as opposed to the Conservatives, whom she accused of being on a “wrecking mission” and having “their head in the sand” regarding green issues.

The group said one of the protesters was student Dieudonne Bila, who said in a statement: “I disrupted Keir Starmer’s speech because I desperately want to see a future government committed to protecting people here and all over the world from the climate crisis.

“We won’t stand by and allow private companies to continue making billions as heating becomes unaffordable, or be silent in the face of extreme heat, flooding and droughts.”

Once the pair had been escorted off stage, Sir Keir told the audience to applause: “I think they may have missed the fact that the last mission I launched was on clean power by 2030 which is the single most effective way to get the green future that they and many others want.”

Labour last month scaled back its flagship pledge to invest £28 billion a year in a green energy transition, saying it would ramp up spending rather than hit the sum in the first year of a Labour government.

Shadow chancellor Rachel Reeves said the decision had been taken due to the dire economic backdrop, with Labour having made financial prudence central to its plan to win the next election.

But Sir Keir said “there’s no U-turn at all” when asked about it in the Q&A, insisting he was “doubling down on it” with his clean power by 2030 mission.

The former director of public prosecutions also condemned the “huge arrogance” involved in the disruptive protests of groups such as Just Stop Oil.

“When I put what they’re doing against what we set out in our mission about clean energy, about net zero, you can see the difference between protest and power,” he said, pointing to the contrast between “gluing yourself, interrupting, interfering with other people’s lives” and the “actual change” a Labour government can bring about.

His speech focused on the last of the five missions set by the party, which is well ahead of the Conservatives in opinion polls – a pledge to “break down barriers to opportunity”.

The measures he set out included teaching youngsters speaking skills, boosting vocational training including with a new national skills plan, expanding mental health access for new parents, and recruiting more teachers in shortage subjects.

A Labour government would modernise the national curriculum, Sir Keir said, but appeared to rule out proposing changes before the next general election.

“I think the case for change is compelling. I’ve set out the principles that we would want to underpin the review, but I do think it is best that that review is done in government when we’ve got the ability to bring everybody together behind what will be a really important change in our education system.”

Sir Keir promised to focus on improving standards in state schools, which Labour says would be funded by axing tax exemptions for private schools – a move the party expects to raise at least £1 billion.

This would include recruiting more than 6,500 teachers and introducing a requirement for all new teachers to hold or be working towards qualified teacher status, Labour said.

At the heart of Sir Keir’s mission is abolishing the “snobbery” he says surrounds an “academic/vocational divide” in education.

Both types of learning should be valued equally, he said in his speech.

“This isn’t a zero-sum game. If we grow the talents of every person in our country – that benefits everyone,” Sir Keir said.

Sir Keir said he is not “pretending we can snap our fingers” and fulfil his pledge to get state schools as good as private schools, but said he hopes to achieve it in about five years.

He told Sky News: “This is intended to set out what I would have hoped to have achieved in five years of a Labour government, maybe a little bit more. We’re in a bad situation, a bad starting situation.

“I want state schools to be just as good as private schools. I want parents to feel that it doesn’t matter anymore whether you send your child to state school or private school because the quality of education is as good in both.”

But the Labour leader declined to commit to a 6.5% pay rise for teachers, telling BBC Breakfast that “we’ll have to wait and see” what the pay review body proposes for the dispute.

And he questioned whether universal free school meals would be the best use of resources given the challenging economic backdrop, telling a Q&A after his speech that he was not considering extending the scheme across England because of financial constraints.

“We’ve gone down the route of breakfast clubs, but other councils and Wales have gone down a different route,” he said.

“It’s a debate we should welcome as an ongoing debate about what’s the best way here to move forward.”