Undecidable and Decidable Problems in Mathematics: A survey and some reflections, for the centenary of Turing's birth

What are the limits of proof, and what follows? – A timely look at the life and mathematical work of Alan Turing. As we approach the centenary of his birth, this lecture offers a chance to learn more about perhaps Britain’s most famous modern mathematician.

This is the 2011 joint London Mathematical Society / Gresham College lecture.
The other lectures held in collaboration with the London Mathematical Society include:
    Mathematics: The Next Generation by Professor Peter Cameron
    Home Office Mathematics by Professor Bernard Silverman
    Indra's Pearls: Geometry and Symmetry by Professor Caroline Series
    Mathematics and Smallpox by Professor Tom Körner 
    Cancer can give you maths by Professor Philip Maini
    Multiplying and Dividing by Whole Numbers by Professor Timothy Gowers
    Can maths catch criminals and bring them to justice?    by Professor Christopher Budd