A shuttle boat powered entirely by the sun has been launched on the Serpentine lake in London’s Hyde Park. The 14.5m (48ft) Solarshuttle, thought to be the biggest of its kind in the UK, will carry 42 passengers every half-hour between the north side of the Serpentine and the jetty in the south, near the Princess of Wales memorial fountain. It cruises at 4mph and is silent and pollution-free. When not in use and docked, any surplus electricity generated by the boat’s solar panels will be fed back into the National Grid, they say. Designer Christoph Behling was also behind one of the world’s largest solar boats, the Hamburg Solarshuttle, which now ferries passengers across the city’s harbour.