Japanese construction firm says this 'Ocean Spiral' is the underwater city of the future

Homes beneath the waves could have first residents in just 15 years

A Japanese construction company has put forward its proposal to solve the issue of rising property prices – start building cities in the ocean.

The famously ambition Shimizu Corporation has unveiled its template for a modern-day Atlantis, a self-sufficient community that sits on or just under the surface of the sea.

The Ocean Spiral project envisages using huge spirals to connect each watertight residential sphere to the ocean floor, where it would create power in the form of methane-producing micro-organism factories.

This artist impression image released from Japan's construction company Shimizu Corporation on November 20, 2014 shows a modern-day Atlantis, a sphere 500 metres (1,500 feet) in diameter that houses hotels, residential spaces and commercial complexes (AFP PHOTO / SHIMIZU CORPORATION)

Other rare earth materials could also be mined from the seabed, and transportation to get down there would come in the form of spheres travelling along the length of the spiral.

People – as many as 5,000 – would live in a sealed transparent ball at the top of the spiral. It would generally sit above the surface to take advantage of sunlight, but could be retracted under the waves in the event of bad weather.

If you’re thinking it all sounds a bit farfetched, Shimizu has said the first city could be ready for residents by 2030. It would take just five years to build and cost 3tn yen (£16bn) – with later units significantly less.

Speaking to the Guardian, Shimizu’s Hideo Imamura said: “This is a real goal, not a pipe dream. The Astro Boy cartoon character had a mobile phone long before they were actually invented – in the same way, the technology and knowhow we need for this project will become available.”