Gerry Northam introduces his selection of highlights from the past week on BBC radio. Programmes featured: Six O'Clock News - Radio 4 The Call - Radio 4 MI6: A Century in the Shadows - Radio 4 Marmalade for Comrade Philby - Radio 4 Joan Armatrading's Favourite Guitarists - Radio 4 Marc Riley's Musical Time Machine - Radio 2 Crossing Continents - Radio 4 Mind Changers - Radio 4 Just A Minute - Radio 4 Round Britain Quiz - Radio 4 Words And Music - Radio 3 Prom 17: Bach - Radio 3 The Adventures of Sexton Blake - Radio 2 With Great Pleasure - Radio 4 Today - Radio 4.