Alan Turing private notebook to be sold at auction

A notebook belonging to the man who helped break the Nazi code, Alan Turing, is to be sold at auction.

The book, which has never been seen in public before, dates back to 1942.

It showcases his mathematical genius, and gives an insight into his private thoughts.

The book is expected to fetch a large sum when it goes on sale in April.

Tim Allman reports.