Sir Richard Branson has invested in the futuristic transportation technology Hyperloop, promising to build the "world's most revolutionary train service".

Sir Richard led a $85m (£65m) investment in Hyperloop One, a California-based company that is the first to successfully test the high-speed magnetic levitation technology. As part of the deal the company will be renamed Virgin Hyperloop One and enter Sir Richard's Virgin Group umbrella.

Hyperloop, the brainchild of Tesla chief executive Elon Musk, involves pods being propelled through a near-vacuum at speeds of up to 700mph. Musk has proposed the system as a new form of high-speed travel that could cut the time between cities from hours to minutes.

Sir Richard joined Hyperloop One's funding round last month, which valued the company at more than $700m.

Virgin Hyperloop One will join Sir Richard's sprawling business empire, which includes high-speed rail investments in Virgin Rail and his space flight venture Virgin Galactic.