I have always wanted to be a diver. So at the centre where Tom Daley once trained, I aim to graduate to a five-metre board – arms locked, bend, one, two, go …

I’m standing on a five-metre diving board – about the height of a two-storey building – preparing to throw myself off, headfirst. And I’m terrified. I take a determined step towards the end, lock my arms above my head and begin to tip forward.

I have always admired people who can dive, and secretly wished that I could do it. I watch them tak...