Sir Keir Starmer said he will never give up supporting campaigns against injustice as he reflected on causes he had helped in office.
The outgoing Prime Minister, who will leave No 10 on Monday, told a reception attended by campaigners whose causes he had championed that they had “made me who I am”.
Speaking shortly before guiding the Hillsborough Law through its final Commons stages, Sir Keir praised the families who had fought for justice.
As well as those touched by the 1989 Hillsborough disaster, guests in the Downing Street garden included John and Penny Clough, who campaigned to get bail laws changed after the murder of their daughter Jane; Figen Murray who campaigned for changes to public safety laws after the death of her son Martyn Hett in the Manchester Arena bombing; and Pooja Kanda who championed tougher knife laws after her son Ronan was stabbed.
Sir Keir, who has two teenage children, said: “I speak as a dad – if anything happened to them, I honestly don’t know whether I would have the strength to do anything about it.
“And yet, I look around this garden, I see people who have lost their loved ones, and they have done something about it.
“And they’ve changed things, not just for themselves, usually not even for themselves, but for other people to make sure that they won’t go through the same thing.
“That has had a profound impact on me, and I can tell you that whatever happens next in my life, I’m never giving up on this.
“As long as I’ve got breath in my body, I’m going to campaign on all these issues with all of you for as long as is necessary.”
He thanked them “for all you’ve done to shape me and make me who I am in terms of the way I try to do my business”.
Sir Keir, who will hand over power to Andy Burnham on Monday, is spending his final days in office highlighting what he sees as his legacy – support for Ukraine and championing domestic campaigns like the Hillsborough Law.
The Prime Minister said: “I leave on Monday. I leave with good grace, I leave very pleased with what we’ve been able to achieve in government in the two years that I’ve had the privilege of being prime minister.
“I’m pleased to have delivered on the promises that I made to many people in this garden, and I’ll make this last promise, which is I will stand with you and walk with you for as long as I’ve got breath in my body.”
He addressed the Downing Street gathering after returning from Paris where he had attended a meeting of the “coalition of the willing” group supporting Ukraine on Monday.
On Tuesday morning, he was with Emmanuel Macron and other leaders at the Bastille Day celebrations in the French capital in a sign of the closer relationship he has tried to forge with European neighbours as part of his post-Brexit rest.
Mr Macron awarded Sir Keir the Legion d’honneur in recognition of his support for Ukraine and European relations.
Sir Keir’s successor is now guaranteed to be Andy Burnham, the former Greater Manchester mayor, who had secured the backing of 369 Labour MPs as of Tuesday.
It is now mathematically impossible for another candidate to secure the 81 supporters necessary to mount a late challenge to succeed Sir Keir, though MP Catherine West, who pulled away from launching a challenge in May, has secured one nomination from fellow backbencher Neil Coyle.
Mr Coyle said he always nominated a woman for leader and had chosen to back a fellow London MP who had previously said they wanted a contest.
Despite being the only candidate, Mr Burnham took part in an online hustings with Labour MPs on Monday, set outting his priorities for the country, including devolving power to communities, improving growth across the UK and tackling the cost of living.
Speaking to reporters on Tuesday, he said people’s everyday living expenses are “the issue of our times” as he was quizzed on his plans for government.
“If we want to connect politics better with people, well, let’s deal with some of the pressures people are under in terms of the everyday cost of transport, the bills that they’re paying. I heard it so often on doorsteps in the campaign,” he said.
“You know, life has changed for people, and it’s not necessarily got better. And I think we just need to be relentlessly focused on that.
“I have talked about more public control of the basics, and then through that control, cutting the cost. I did that with buses in Greater Manchester, and I carry that same principle forward.
“To me, the cost of living and reducing it is everything, and I think we need to regain the confidence in the public that we’ve got a credible plan to do that and make life better.”
Read MoreBurnham says ‘serious review’ into MP safety needed after Widdecombe death
Hillsborough law unanimously backed by MPs
Louise Haigh set to land key policy control role in Burnham government
Queen tells booksellers ‘I hate sci-fi’
Trump backs down over threat to levy tolls on shipping in Strait of Hormuz
Eight-year-old girl among three killed in suspected double murder in Co Antrim
