'The thing I remember now is that twinkle in his eye': Former ITV News Science Editor on meeting Stephen Hawking

• Lawrence McGinty's report on meeting Stephen Hawking in 2013

I interviewed Stephen Hawking twice - not enough to claim even acquaintance, but enough to notice the gleam in his eye that betrayed a man with a keen sense of humour and a thirst for fun.

How else could you describe someone who appeared in Star Trek and the Simpsons, who took one of those flights that simulate weightlessness, and who reportedly used to try to drive his wheelchair over the feet of people who could take the joke?

He was, however, primarily a scientist. And luckily for him, he was a theoretical physicist – luckily because that kind of physics goes on in your head and so his motor neurone disease didn’t hinder his career.

Theoretical physics is tough stuff; unimaginably complex mathematical equations to be manipulated.

Hawking, reputedly, could hold these monsters in his head without the need of a blackboard – it’s a bit like holding all the scores of every match in the Premier League for the last couple of seasons and the goalscorers, except much, much harder.

One of his first discoveries was about black holes.

Everyone knows that black holes suck everything in – matter, radiation, everything. Nothing escapes.

But Hawking found that black holes leak. Radiation escapes from some black holes. They called it Hawking radiation.

But the interesting thing is how he found it.

He combined theories of space, time and gravity – the stuff of the cosmos – with quantum mechanics, the theories that describe how impossibly small things work. That’s typical of Hawking’s boldness and imagination.

• Lawrence McGinty first met Professor Hawking in 1988

The first time I filmed him was in 1988, when his book A Brief History of Time was coming out.

It was raining cats and dogs in Cambridge. We all got very wet.

Hawking had his wheelchair at full throttle.

My cameraman was desperately asking him to slow down so he could get into position for the shots we needed. Sorry, full throttle.

Interviewing him was painfully slow, for us and for him.

We submitted our questions days in advance so he could load the answers into his voice machine.

We wanted all the usual editing shots – reverses, noddies, two-shots etc. He was very patient.

In fact, he wrote the book for money. He realised that if he survived, he was going to need plenty of money to pay for nursing, assistants and so on.

Writing a book was the only way he had of raising those funds.

But he was also keenly aware that science doesn’t exist in a vacuum. He campaigned for the disabled.

He campaigned for the NHS, in the last few months challenging Jeremy Hunt over NHS funding and organisation.

But the thing I remember now, on the day he died, is that twinkle in his eye. That gleam that said, OK I’m a scientist, but I’m a human being too.