One hundred feet below London's streets is the world's first underground farm. A renovated World War II air raid shelter was chosen as the perfect location by Steve Dring and Richard Ballard from Zero Carbon Food, who wanted to grow leafy greens and salads in a sustainable and innovative way. The farm is in South West London and uses hydroponic LEDs, which are in turn powered by wind turbines. Zero Carbon Food will start trading to restaurants this month.

The tunnel system, built during WW2 to protect citizens from German air raids, is rather creepy. But its location in the heart of the city means there are many advantages. Writing on their website, the entrepreneurs highlight a few:

'The immediate benefit for Londoners is reduced food waste through increased shelf-life, bringing employment to inner cities and helping to achieve the reduction in the carbon footprint of the capital. The wider benefits are that our system uses 70% less water versus traditional open-field farming methods, year round production negates seasonality and therefore the necessity to import produce, drastically reducing food miles for retailers and consumers. In addition to this the crops are free from pesticides.'