Are tourists dumb or what?

As well as the heights of Mauna Kea, this summer's jaunt took in the Pacific coral reef off the western coast of the Big Island. We were only a maximum of a hundred feet below the surface, but it was clearly a different world down there, with the colours changing as the water absorbs the light from the surface.

The reef, to my uneducated eye, looked healthy. There were wonderful little yellow fish, called tang, and small shoals of snappers and butterflyfish cruising around. A couple of sea urchins crawled around on the bottom. And I tried to remind myself that coral is actually an animal, and not a plant as it can easily seem.

It was a fascinating glimpse into the life of things that we often only see in aquaria or on the plate at exotic restaurants. But at the start and the end of the trip, why oh why oh why did the submarine tour company insist on playing badly recorded sounds of Klaxons blaring and a voice shouting 'dive, dive' and 'fire torpedo'? Was this our war on coral? Do they think tourists are dumb or what?