Jo Cox was more than an MP doing her duty for her constituents. Her whole life was inspired by an idealism that is itself under attack.
I think I understood Jo Cox – and what she was all about – the minute I met and first talked to her. She was a young woman proud of her Yorkshire working-class upbringing, who had overcome class and gender barriers to get into Cambridge University.
But she then found that Cambridge created barriers of its own – making her, as she said, all too conscious of how she spoke, which school she had gone to, and who her friends were.
It took her a large part of her 20s, she said, to recover from Cambridge, but that experience tested her, and then strengthened her, and made her the amazing person we came to know.
She was never to be afraid again, and her ambition was not to join the establishment but to change it – and to change it for people far less fortunate than herself.
Putting something back in was the key to her activism. Her regular constituency surgeries and local visits made her, in just a year, one of the country’s best-loved MPs.
And there were her journeys to the most dangerous war zones and the most famine-ridden corners of the Earth.
The pathbreaking work she, my wife Sarah and a host of dedicated women undertook together significantly reduced the number of mothers dying in childbirth.
I knew Jo as the loving mother who would do anything for Cuillin (named after the Scottish mountains she loved) and Lejla (named after a Bosnian nurse who inspired her and her husband Brendan). Now the two girls must grow up with no mother there beside them: to take them through their teens, or to talk to when they find partners.
But I do know they’ll grow up not only surrounded by love and proud of everything she achieved.
And the Jo who cut across the often suffocating conventions of Westminster should be remembered as much more than the brilliant, effervescent and seemingly irrepressible MP who sought to help those in need.
Indeed she would not want to be remembered for that alone.
Her life was devoted to building a different kind of world – one in which we owe more than a general responsibility to one another.
She wanted us to shout from the rooftops, as she said in her maiden speech, that there is much more that brings us together than drives us apart.
She believed our society’s diversity was our greatest strength.
She wanted us to do more than adhere to “a golden rule” – that we should love our neighbour – and actively seek equality, particularly for those who are dispossessed.
And as Brendan told us, she would not want us to confront hate with hate, but to conquer hate wherever it is found.
Jo’s death – and how it happened, and how we should honour her memory – raises difficult questions for all of us. We need to start answering them in what remains of this referendum campaign.
We, the British people, pride ourselves on being different – that here in the UK we both reject the extremes of prejudice and are a nation built on tolerance. But as Jo would have been the first to tell us, we have been witnessing a downward spiral in our political culture.
The business of politics has become more about the exploitation of fears than the advancement of hope.
Temperate language has given way to the intemperate.
And where there is latent prejudice, we have seen it exploited to breed intolerance – and then too often intolerance has descended into hate.
The referendum was always about more than Europe; it was always about what kind of Britain we are and what we aspire to be.
But some have attempted to hijack a decision on the future of Britain in Europe and turn it into a vote on immigration, and then on immigrants and those who support immigrants.
Unless we strive for a culture of respect to replace a culture that does too little to challenge prejudice, we will be learning nothing from what happened to Jo.
We have to be honest that calling for tolerance, while welcome, is not enough. We cannot just revert back to a status quo still filled with prejudice and discrimination without recognising the hurt that has been done and the need to address these injustices head on.
Only by tackling the prejudice and hate that killed her can we do justice to the meaning of Jo Cox’s life.

- Gordon Brown, former prime minister and chancellor of the exchequer of the United Kingdom, is UN special envoy for global education.