As a small taste of Channel 4's The Ultimate Film we're bringing you previews of 4 of the 100 films that make up the most popular films in British cinema history. Check out our intros, read reviews and watch a brief clip from each of the films.

The Dam Busters

Chocs away for a stirring tale of wartime heroics as the RAF hit the enemy where it hurts. Barnes Wallis invents the 'bouncing bomb' to destroy German dams. Read the review Watch clip: low | high

The Third Man

Orson Welles's Harry Lime steals the show (and anything else he can get his hands on) in this stunning noir set amid the ruins of post-War Vienna. Read the review Watch clip: low | high

The Blue Lamp

London never looked so good as in this classic in which Jack Warner's PC Dirk Dixon is on the trail of Dirk Bogarde's amoral killer. Read the review Watch clip: low | high

Carry On Nurse

The men's ward is causing trouble at Haven Hospital in this classic Carry On from 1959. Oh Matron! Watch clip: low | high

All images and clips courtesey of Canal+ Image UK Ltd.