He was educated at the former Hitchin Grammar School. He did not go to university.

Whitmore is best known as a BBC newsreader in the 1970s and 1980s. He is also the author of several books, the latest (2007) of which is a biography of Reginald Hine, an historian from Hitchin who committed suicide in 1949.

He famously appeared (along with other presenters and newsreaders) in the 'Nothing Like a Dame' musical number on the Morecambe and Wise Christmas Show in 1977,and has since also performed professionally on the stage in several productions.