When available it is expected to be adopted rapidly and be $6 billion industry by 2018.

It works by switching and existing LED lights on and off at a very high rate that is imperceptible to the human eye. In ideal situations researchers have achieved 224 Gbit/s (18 x 1.5GB movies a second) and using reflected light up to 1Gbit/s.

PHY III – the current standard - is rated from 12Mbits to 96Mbits but this technology is also rapidly developing to include colour shifting.

Because it uses light instead of radio frequency (RF) it is safe to use in aircraft and its signal is contained to the area around it – no leakage outside the walls.

The downside is that most devices including IoT already have internal Wi-Fi and this requires a colour sensor, new hardware controllers, and software. LEDs would also need to access a controller.

Li-Fi was invented by Harald Haas from the University of Edinburgh, Scotland in 2011. For the first time he demonstrated that by flickering the light from a single LED, he could transmit far more data than a cellular tower.

It uses visible light between 400 and 800 terahertz (THz). It works basically like an incredibly advanced form of Morse code.

Haas said, "In the future we will not only have 14 billion light bulbs, we may have 14 billion Li-Fis deployed worldwide for a cleaner, greener, and even brighter future."

Future advances include adding a receiver layer to smartphone and watch screens and also transmitting a small amount of power to them – to top up rather than recharge the battery.