During the course of the seven years I played scenes with an oil slick, I played a scene with a grain of rice. Sometimes with indescribable creatures. I remember having a conversation with something which was simply a smell, that's all. It was part of our job.

Creating a believable world on the ship was very important, and technically they got better and better and better at showing the ship too.

Where can I go that would give me the same level of satisfaction as an actor?

In the first couple of years I spent my weekends, Saturdays and Sundays, preparing for the next week, because otherwise you would never catch up.

Encouraging people to believe in it was the most important thing of all. It's one of the reasons I was always uncomfortable whenever film crews came on the set to shoot things. I didn't want our make-believe to be exposed.

During my time we had two chairman of the joint chiefs of staff, at different times of course, on the bridge, both of whom asked my permission to sit on the captain's chair.

We were well into our second season before all of us got that look in our eyes that maybe the predictions had been wrong and that it wasn't going to end after two years or three. The fact that it was to go on for seven-if I had known that I would never have been part of it in the first place.

As the captain, I was going to be having the dominant role in most of the episodes, and that was appealing. I wasn't interested in coming to Hollywood to sit around.

It was a long time before any of us realised that we were very slowly becoming well known as actors. That was a very, very slow process, largely brought about by the fact that we were too busy working to lift up our heads and pay attention to what was happening.