The astonishing £15.6trn mega-project that would link the UK with US in just 54 minutes!

The tunnel would stretch 3,400 miles under the Atlantic Ocean, which in some places is thousands of metres deep.

The Channel Tunnel took six years to build

It once took Concorde around 3.5 hours to whisk passengers from London to New York at the height of its fame. The supersonic aircraft was able to travel at a cruising speed of Mach 2.02 - roughly 1,345 miles per hours - as it sped across the Atlantic.

Concorde was not cheap, with a round trip ticket costing around US$7,574 back in 1996. It was, though, a popular form of transport with celebrities, royalty, and high-profile business executives - helping to enhance its image as a symbol of prestige and luxury. 

However, it could soon be possible to travel across the Atlantic in just under an hour, if the green light is finally given to an ultra ambitious infrastructure project.