Darek Fidyka, a Bulgarian fireman, was injured in a knife attack in 2010, which left him paralysed from the chest down. He has received pioneering surgery which involved transplanting cells from his nose into his spinal cord in the first practical application of stem cell surgery of this kind.

Professor Geoffrey Raisman, whose team at University College London’s institute of neurology discovered the technique, told the Guardian: 'We believe that this procedure is the breakthrough which, as it is further developed, will result in a historic change in the currently hopeless outlook for people disabled by spinal cord injury.'