Despite never coming to fruition, back in 2012 Boris Johnson proposed a radical plan to build a £58.9 billion floating airport in the River Thames. Dubbed Heathrow 2.0, the drastic solution to airport capacity issues involved floating platforms, check-in miles away from the airport, and being built near a sunken World War II warship filled with explosives.
The plan came about because Heathrow, the UK's busiest airport, was always operating at full capacity, which left little room for bad weather, delays, or surges in demand. Other options like expanding Gatwick or Stansted were either impractical or costly, and a multi-billion Heathrow expansion would require demolishing nearly 4,000 homes and rerouting rivers and the M25 motorway.
So in came the so-called Boris Island, a massive six-runway hub in the River Thames at Kent's easternmost point, which would have been capable of handling 150 million passengers every year, nearly double Heathrow's capacity.
Takeoff and landing would have been over water, but it meant the runways would have had to be accessed through high-speed rail tunnels after check-in at multiple passenger terminals in London's train stations, or new purpose-built floating platforms.
It was suggested that it could replace Heathrow entirely, with the old site being turned into a new London Borough with 300,000 homes - despite the fact that many companies had set up around the airport for quick international connections.
However, naysayers believed it would rapidly surpass the £58.9billion estimate as there were huge risks involved.
There was a sunken warship near the proposed site with more than 10,000 unexploded bombs on board, and a nearby island was home to one of the largest highly flammable liquefied natural gas terminals in the world.
The Thames also attracts thousands of birds, which could have interfered with aircraft engines, and the Met Office said the area would see three times as much fog as Heathrow throughout the year, which would ultimately reduce capacity.
The airspace was also already crowded with existing flight paths, and ultimately Boris' big plans never came to fruition.
The then Mayor was such a huge advocate he had brought together architects, marine experts, environmental specialists and aviation professionals to develop the £58.9billion proposal.
