Simon Singh is well known for his work on coding, maths and science and has written books such as The Code Book, Trick or Treatment? Alternative Medicine on Trial and The Simpsons and Their Mathematical Secrets.
He has also been involved at CERN, the European Organisation for Nuclear Science.
Yesterday he gave a talk to a group of Grammar School and Elizabeth College students about the Germans' Second World War-era Enigma code and the history of codes and code-breaking.
He brought along his own Enigma machine and demonstrated how it worked and also spoke about his love for science and mathematics.
'I think science is incredibly important and thinking scientifically and mathematically is crucial,' he said.
'Our brains are so keen to find information that if it is looking for something, our brain can trick us into believing anything – things need to be looked at objectively, not subjectively.'
Mr Singh also spoke about how the Enigma code worked, how it was cracked and the importance of it in the war.
