I can't call Jo a close friend but I came to know her quite well over the last year. We went to the same college in Cambridge, though she had graduated by the time I arrived (and wasn't particularly sentimental about her time there). Jo was a New Statesman reader and she contacted me after an article I wrote about the failure of the UK and others to do more in Syria - failing to protect the civilian population from atrocities committed by both the regime and Daesh.

We talked on the phone and then met up at Portcullis House to discuss British foreign policy, and the current state of the Labour Party. As a newbie in parliament she was finding her feet but, from the outset, she was bold and brave - not afraid to challenge conventional wisdom or, when she thought it right, leadership. She was one of those rare people with a deep moral integrity but no interest in grandstanding or moralising herself. She was not a contrarian or a troublemaker and much preferred getting on with people - in fact, it was impossible not to like her. She was independent in spirit and mind, and full of energy and a sense of urgency.

This is perhaps no surprise given her distinguished past career, as a humanitarian and an activist. Very simply, she was passionate about helping people, and doing good. That's why she went into parliament. That's why she also wanted to be in government at some point (and appreciated that being in power really did matter). She believed that government could be a force for good in people's lives, at home and abroad. She also believed that Britain was nothing if it wasn't outward looking, and doing good in the world.

Two weeks ago I met Jo at Westminster and we walked up to a dinner in Covent Garden. She had agreed to address a group of American summer school students I was teaching. On the walk there, I offered to push Jo's bike as she was finishing an article for the Times on Syria, and simultaneously speaking to leaders of the Syrian opposition engaged in the UN-backed negotiations (the image of the multi-tasking mum). She was full of energy and warmth and admiration for her Syrian friends. They were hugely grateful to her, believing that they had a true friend in Jo, when so many others had forgotten about them.

Politicians have so many demands on their time, but Jo really enjoyed the evening, talking to young people, and hearing different perspectives. She talked about volunteering on the first Obama campaign but said she had become a little disappointed with aspects of his foreign policy since. The students were blown away by her passion. Inspirational is an overused word but that is exactly what Jo was. A few of the students have already contacted me to say how heartbroken they are. It's not an exaggeration to say that she was the type of person who would restore one's faith in politics - to make you see the point of the whole thing. She looked like a future foreign secretary, or a future leader of the Labour Party.

I last saw Jo on Tuesday of this week in committee room 6 of the Commons. We have been working on a report which we were planning to publish after the Chilcot Report. It was to be co-written with Tom Tugendhat, the Conservative MP and another of the new generation who came into parliament in 2015. The report was to argue that Britain should not retreat into its shell but should retain an active and outward looking world role (with humanitarianism being a central aspect of that). Jo had no hesitation in working with someone outside her party. She knew she would come in for criticism but she wasn't worried at all about that. She was encouraged at the growing interest in a cross-party effort of this kind. She had previously joined forces with Andrew Mitchell to argue that Britain should do more on the humanitarian front in Syria, so working across the aisle was something she regarded as really important.

When I saw her, Jo was in her running gear and had to dash home as one of her children had chicken pox. She said she was tired, having been sleep deprived looking after her kids, but she showed no signs of it. She was unfailingly charming and bubbly and extremely sweet and funny. Her mind was as sharp as ever. I never met her children or husband but one can just tell she was the perfect mother and wife. She had angelic qualities. She might well be the best foreign secretary Britain never had. The best tribute to Jo is to keep alive the things she stood for.