Rob, 37, is a watersports fanatic. And along with friend Dan Piazza, 52, he has turned his hobby into a thriving business.

The pair built their first submersible 12 years ago and today their company, Innespace, has a year-long waiting list of rich adrenaline-junkies eager to buy one of their custom-built playthings.

Toys they may be, but each one costs about £60,000.