An attempt by BBC television presenters to cross the Solent in an ice boat failed when it melted and sank.

The idea, from the science show Bang Goes The Theory, was to test a Second World War theory by inventor Geoffrey Pyke that warships could be made from frozen water.

But despite storing the boat in one of the UK’s largest ice warehouses, in Tilbury, Essex, for three weeks, the craft sank not long after departing Gosport Marina.

Lynette Slight, production coordinator of the show, said: ‘They had just got out of the marina when it began to sink.

‘It was all a little bit strange. I don’t think they realised what was going to happen. In the end it just tipped upside down.

‘It was taking on too much water at the back and the engine became too low.

‘They thought they could get it to Cowes – they couldn’t, but you never know until you try it.’

During the war Pyke suggested that, in the event of steel stocks running out, it was possible to make an unsinkable aircraft carrier using pykrete, a material made of ice and wood pulp.

He claimed that the mixture could be moulded into any shape and, with a slow melting rate, it was thought perfect for seafaring vessels.

The BBC’s plan was to mix 5,000 litres of water with the hefty material hemp and freeze it into a 20ft-long boat.

The show’s presenters – Jem Stansfield, Liz Bonnin, Dallas Campbell and Dr Yan Wong – then attempted to sail it to Cowes with an outboard engine.

But after an hour in the water the boat capsized after taking on water.

The presenters had to be rescued and the melted boat was towed back to shore.

Giles Harrison, director of the show, said: ‘I think we’ve proved that Pykrete works but it is unstable.’

The ice boat episode of Bang Goes The Theory will air on BBC1 at 7.30pm on October 13.

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