Sir Bernard Silverman (Class of 1969)


Sir Bernard Silverman was knighted in the 2018 New Year’s Honours List, for public service and services to science. After leaving CLS in 1969 he studied Mathematics at Cambridge and held senior academic roles at Bath, Bristol and Oxford Universities. Sir Bernard was Chief Scientific Advisor to the Home Office (2010-2017) and continues to work in industry, government and academia. He was interviewed by the School’s Alumni Office.

How did you come to be a pupil at CLS?
I was good at maths as a child, a sort of prodigy, and I suspect that my parents didn’t really know what to do with me. They found out about the City of London School and thought that it might work for me – and it did and it was great.
I went there when I was nine. I used to go on the Tube. I could have gone when I was eight, but I was only about 3ft 6in tall and the idea of sending me on the Tube at that age was probably a bit too much for my parents. I was at the junior school for two years and I stayed until I left after my Cambridge entrance exam.

I had a scholarship. That’s one of the reasons I’m very keen on supporting people through the bursary system now. My hope is that we can give opportunities to other people in this way.

What was the school like in the 1960s?
London wasn’t fun like it is now; it was rather dreary. There weren’t so many people around and when you got out of the Tube at Blackfriars you could still smell the river. They widened the embankment while I was at school and cleaned up the river. But at the beginning of the ‘60s, the Thames was really smelly and if you fell in, you had to have your stomach pumped. A lot of the people that taught us had been there since the 1930s, or even the late 1920s. They were an interesting, quirky, slightly old-fashioned sort of group. I really thrived because being a bright kid was not a problem there.

We went to galleries and I got into music. I have always been interested in politics and public life and we used to have speakers coming all the time, as we were only just down the road from Westminster.

Margaret Thatcher came when I was 12. I asked her a question and she took me completely seriously, though later in life I realised she probably spoke to everyone as if they were about 12! I ended up chairing the debating society and I was a very keen member of the Army cadets, too.

I still see Terry Heard, my old maths teacher. He’s only about ten years older than me. When I was at school, he’d just been to Cambridge and then come straight back to the School. The School was diverse for its time. It was quite socially mixed: school fees were much lower in those days and, in any case, there were a lot of free places and scholarships. I don’t think many people in my own class actually paid to go there.

What opportunities does the School give a bright child they wouldn’t get elsewhere?
It’s to do with being able to give maybe slightly quirky children real attention and getting them into a place where there are lots of other people like themselves. If they are getting on well where they are, fine. But the feedback you get from people who have gone to the School after their GCSEs is that the School has opened vistas and horizons that they wouldn’t have known about. So that’s very important.

Everyone will want to know about your work on the first programmable pocket calculator
I was a graduate student at Cambridge and I was a bit bored, frustrated. I was on track for an academic career. I was approached by [maverick inventor] Sir Clive Sinclair to go and work with him. So I agreed to take a year off from studying and see how it went. I went there and worked on the programming and the design of the Cambridge Programmable Calculator. Which is now in museums. We had a very small amount of space on the chip we were using, both for the program and the memory. The memory was measured in bytes; not even kilobytes. You had something like 128 bytes to make a whole calculator work. It was really interesting, a really good experience.

We had to save money in every aspect of the manufacture. So the calculators weren’t altogether reliable – and the battery used to run out very, very quickly. Nevertheless, the idea was brilliant. Sir Clive Sinclair was very visionary but also somewhat prone to cutting corners, and things didn’t always work out for him.

Was that the most exciting time to be involved in your field or would it be more exciting to be starting out now?
It was very exciting then. I got a real insight into how business works. I remember him saying to me once that we could program the chip we were using to make an ‘individual computer’. And I said, ‘Well why would anyone want one of those?’ I should have realised that computers would be used for so many other things, not just mathematical problems.

When I went back to University, my PhD was all about using computers to solve statistical problems and understanding the maths behind that.
I’ve always been keen on having the latest computers and gadgets and so on. It amuses me when people say that being online is a young person’s thing.

You’ve carried out significant work at the Home Office on human trafficking and modern slavery… at what point did you start to feel your work was making a difference?
I was Chief Scientific Advisor to the Home Office which was a dream job for me because it combined working across different scientific areas with my interest in public life and politics. My job involved scientific work of my own, facilitating the work of others and explaining things to government ministers and civil servants and so on. That pressed all my buttons. It was wonderful. One day, the then-Home Secretary Theresa May’s advisor rang me up and said they were working on a Modern Slavery Act and they would like to know how many victims there were; so I started looking into it. You can’t just count the number of victims by seeing how many are reported to the police. Most victims never come to light.
I realised you could make an estimate by analysing the different numbers of cases on different lists and using a mathematical approach to give you an idea of how many cases were not within the data at all. That led me to a figure of 10,000-13,000 – a figure that has entered the public consciousness. It was all over the newspapers. 

That figure was the result of a rigorous scientific approach to a problem of enormous public and ethical importance. And so I was very proud to have done that.

In your TED talk you explain a complex mathematical model by comparing it to a method of calculating the number of fish in a pond…
Well, my view is that a good scientist should be able to make difficult things appear simple, rather than the other way round.

What other projects did you find particularly satisfying, while you were at the Home Office?
I worked on the subject of how long police should keep DNA of suspects arrested for crimes but not, in the end, charged. We looked at the Police National Computer and found some of those people do end up being arrested again and charged and convicted. But after about three years the risk of that happening falls to about the same as that of the general population. And that finding became part of the Protection of Freedoms Act.

Now, you seem to have many and various roles…
One interesting thing I do is chair a committee of the Census group at the Office of National Statistics, which is designing the next census in 2021. We are working on ways to get the best possible information while protecting people’s rights to privacy and anonymity.

Is there a field which statistics has yet to impact?
People used to say mathematics wasn’t much use, except to teach mathematics but now data science and machine learning are transforming almost every aspect of our lives. The challenge, as with any transforming technology, will be to figure out how to reap the enormous potential benefits without doing harm or leaving people behind.

You love cutting-edge tech – what’s your current favourite?
My electric car! I just love my BMW i3: I can send it an email to do things like switch on the heating before I get in. It’s wonderful. For Sir Clive Sinclair, batteries were always the problem. But now they’ve solved it – I can drive my car all the way to Oxford and back on a single charge. The design that goes into modern vehicles is fantastic – and I’m really looking forward to having an autonomous car.


I had a scholarship. That’s one of the reasons I’m very keen on supporting people through the bursary system now.

George Hodgson (Class of 1999)

Former ambassador to Senegal
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