Scientists are monitoring the progress of a 390-metre wide asteroid discovered last year that is potentially on a collision course with the planet, and are imploring governments to decide on a strategy for dealing with it.

Nasa has estimated that an impact from Apophis, which has an outside chance of hitting the Earth in 2036, would release more than 100,000 times the energy released in the nuclear blast over Hiroshima. Thousands of square kilometres would be directly affected by the blast but the whole of the Earth would see the effects of the dust released into the atmosphere.

And, scientists insist, there is actually very little time left to decide…