An experiment run by the BBC to make a boat out of ice has hit rock bottom

An experimental motor boat made of ice has sunk in Portsmouth harbour. It had set out from Gosport marina to cross the Solent, but its crew of four BBC presenters was forced to jump into the water when it started melting and sank.

The boat had been built to test the properties of the World War II invention ‘Pykrete’, ice made from water mixed with wood fibres which formed a much stronger solid than pure water ice. Scientists had planned to use the material to build huge aircraft carriers over 600m long and weighing 1.8 million tons.

The boat which sank was developed as a project for the BBC science programme Bang Goes The Theory. It weighed a mere five tons which, said a spokesman for the Royal Society of Chemistry, made it much more susceptible to melting than a much larger vessel.