Francis and Sue Williams reckon they've made £4 million from MoonEstates in the last four years. The firm holds the UK rights to sell parts of the Moon, Venus and Mars.

They were granted the rights by Dennis Hope, an American who exploited a loophole in the 1967 Outer Space Treaty to claim ownership of every planet in the solar system.

Mrs Williams told This Is Money:

"There have been so many stories about the Earth and global warming.

"We are simply offering the chance to live on another planet. We think in about 15 years' time it will be viable to go to the Moon."