There are a lot of reasons why the day after the 2019 general election will be permanently seared into my memory – most of them bad. The sense of disappointment, of the people we had let down, of the harm that five more years of Tory government could do. But there was one moment that makes that day stand out for another, happier reason. That was the day that Lisa Nandy called me to say she was considering standing to be the next leader of the Labour Party.

As we collectively reeled over the devastating result, sharing campaign war stories and beginning the grieving process for the many brilliant MPs who we had lost as colleagues and comrades, Lisa’s analysis and vision were as clear and compelling as ever. Lisa has a knack for telling the truths that others don’t want to see and can’t bring themselves to say. She did that from the off: telling us that we can’t just carry on as we are, that one more roll of the dice – in any sense of the word – was not going to cut it, that we have to change and change urgently or else, as a party, we faced irrelevance and extinction.

That message is a tough one to swallow. Change is never easy, especially when it involves unpicking the way that things have been done for decades, but I knew then what I believe has been proved throughout this campaign – that Lisa is the right person to lead that change, and that she has the courage, the judgement and the values to help Labour become a party of government again. You can’t treat a problem that you struggle yourself to see. Lisa’s clarity gives her the edge over the other candidates in this race. It gives her a head start in getting us back into government and back into a position where we can change lives.

Having known Lisa for a decade, I have always been able to say with my hand on my heart that she is genuinely one of the most talented, intelligent and thoughtful people I know. Of course, we all love our mates and all wish that everyone could see what we love about them, why we love them. One of my favourite things about this campaign has been watching as members have got to know her, have learned for themselves about the qualities I see in my friend, have come to love her too.

I have travelled around the country with Lisa – to seemingly endless hustings and member meetings – and have watched her win the room time after time. She spoke to the country and showed us how you not only win over the ‘Red Wall’, but you build a red bridge back to victory. I’ve seen her unite and inspire people that you would never expect in a million years to give her the time of day, let alone to agree with her. Bringing people together, building surprising alliances – that is Lisa’s way.

I am so proud of the coalition that we built, from the GMB to George Monbiot, and from Vauxhall to Bassetlaw. But nothing sums up the campaign more than as chair of Labour Friends of Palestine and the Middle East, Lisa securing the Jewish Labour Movement nomination. Lisa’s campaign reminds the Labour Party that we are more than the sum of our parts, that we are stronger together, that no faction matters more than a united Labour that can win.

Lisa builds teams of people and empowers them to deliver change. I’ve watched her do it in her time as an MP, and I’ve been at the heart of it on her campaign – a campaign driven by volunteers because we simply didn’t have the funds to recruit many staff, a campaign fuelled by the energy and enthusiasm of Labour members who have gone above and beyond in what has been a long and at times gruelling contest. They did that because Lisa put her trust and respect in them, and inspired them to support her vision.

And it was their energy and passion that drove so many of the ideas that we have put forward during the campaign, from speaking with Danny Boyle on the Olympic legacy – the first time he had ever spoken publicly about it – to working with Syrian refugees. From campaigning for reform to the honours system to demanding tax justice and a green industrial revolution. From redesigning our welfare system around the people who use it to giving voice to the countless women and men across our movement who are desperate to see our party finally led by a woman.

This is the Labour Party that I want to be part of and represent, and it’s the kind of society that I want to help build – one that draws on the talents and aspirations of everyone and gives them the resources to achieve. Leadership in modern Britain isn’t about pretending to be some sort of saviour. It isn’t about having someone take our problems away from us. Leadership is about creating the conditions and the means to equip and empower people to make their own decisions and build their own lives. Lisa understands this more than anyone I’ve ever known. She is fearless, principled and, in these troubled political times, her leadership and her analysis are exactly what our party and our country need.

Whatever happens this week, I couldn’t be prouder to have worked to make Lisa our next leader. This campaign has given me fresh hope and fresh energy. And confidence. That however dark today may seem, Labour’s future can be bright again.