Alan Turing's nephew on how Poles helped crack Enigma code

Sir Dermot Turing, nephew of World War Two code breaker Alan Turing, pays tribute to the role of mathematicians in Poland in cracking the Nazi Enigma code.

It has long been said that the breakthrough shortened the war by two years, saving countless lives.

The work of the Polish experts involved will be honoured at the Polish Embassy in London on Saturday.