Stephen Hawking will return from the CERN collider today to unveil the new clock at Corpus Christi College in Cambridge, England. The unusual clock was designed by inventor John Taylor.

For all its apparent eccentricity, the clock is based on solidly traditional clockwork - unusual in these days of digital electronic clocks. It has taken seven years’ research and construction, incorporates six patented inventions, and is predicted to run for at least 250 years assuming the world lasts that long.

Engineer Stewart Huxley refuses to reveal the secret of its tricks, which include the pendulum occasionally apparently catching and stopping for a heartbeat, and then swinging faster to catch up.