Frederick Sanger: Double Nobel Prize winner dies at 95
20 November 2013 Last updated at 18:12 GMT
Frederick Sanger, the British biochemist who twice won the Nobel Prize, has died at the age of 95. He has been described as one of the greatest scientists of any generation.
Prof Sir John Walker, who himself won a Nobel Prize for chemistry in 1997 and worked alongside Dr Sanger, described his work as "an astounding achievement".