A leading British scientist has warned that plans to bring back material from Mars could imperil the Earth should people come into contact with Martian microbes. Dr John Murray, a scientist connected with Europe’s Mars Express mission reportedly believes that life is to be found on Mars, but he thinks it likely that it will be discovered in a dormant state, frozen in ancient Martian ice deposits. Murray has been leading a team at the Open University in the city of Milton Keynes who have been examining fractured features on the Martian surface that are akin to ice formations on Earth. If this is the case, it may indicate the existence of a submerged sea, 800 to 900 kilometres in size and with an average depth of 45 meters. Since the sea will date back to a much earlier era in Martian history, any primitive life that may have existed will be frozen in time. Murray is proposing a two-stage mission to validate his hypothesis, the first a probe to smash into the ice and blast out a crater, the second to land and revive any slumbering microbes. But Murray is cautious about the prospect of bringing anything living back from Mars. H.G. Wells imagined Martian invaders dying of common earthly diseases, Ray Bradbury sent colonists to Mars who infected and wiped out a Martian civilisation, but to bring Martian microbes to Earth may well prove equally cataclysmic, should one of them prove to be a virulent pathogen to which we have no natural immunity.