A moment that changed me: Ken Follett – killing time, I found the inspiration for my most successful novel

I was brought up in a puritanical religious sect but a chance visit to Peterborough cathedral began a lifelong interest in these wonderful buildings

In the mid-70s, when I was a young reporter on the London newspaper the Evening News, I was sent to Peterborough - then pretty much on the edge of the paper's circulation area - to do a story. I had finished my interview, and had an hour to wait until the next train back to London, so, having nothing to do, I went to look at Peterborough Cathedral.

As you approach it from the west, there are three huge arches: they look like doorways for giants. Inside, I looked around and was completely fascinated. Most people who look at a cathedral feel this, usually asking themselves two questions: why did medieval people want one of these? And how did they build it?