'It sounds like one of Steve Wozniak's celebrated pranks. Woz, as he likes to be known, the other co-founder of Apple Computer, owner of the first dial-a-joke service in the San Francisco Bay area, took a phone call a few months ago from a friend who invited him to invest in a new company. Nothing odd about that, except there was a catch: it wasn't allowed to know in advance what it was going to do. 'It's a Special Purpose Acquisition Corporation, or Spac,' says Woz happily, 'whose job is to acquire some company to do something - which we're in the middle of doing right now, so I can't tell you too much about it.' He admits it's hard to believe - 'no one had ever heard of this weird kind of company that could go public and not be allowed to know what it's doing' - but he found the unexpectedness of the project instantly attractive. So he said yes.

In fact, the company being acquired, for $260m (£136m), is a California chip foundry called Jazz Semiconductor, which makes super-fast chips that the new owners hope will be at the heart of converging generations of mobile phones and other wireless consumer products. Woz will be chief technology officer, and thus finds himself back in the established corporate world that he hasn't inhabited since he left Apple in 1985. Woz, a genial, bear-like 56-year-old, is in the UK to promote his as-told-to autobiography, iWoz, and as he emphasises in the book, pranks have done him well. The dial-a-joke line, run from a kitchen in Cupertino, netted him his first wife, one of its customers, before he had to give it up because (typically) it was costing too much. Among the projects on which he honed his nonpareil technical skills were early computer games and the famous 'blue box'. This was a device for making free long-distance phone calls with which he once narrowly failed to wake up the Pope. On both occasions his partner in crime, as it were, was another prankster by the name of Steve Jobs.'