This is a delight. Not a horror movie but a suspenseful crime-mystery, it commences with a robbery on Tower Bridge and proceeds quickly, following the loot, to rural England where murder and black-mail are set in motion at a resting out-of-season circus. Klaus Kinski's robber lurks scowling in the shadows, Christopher Lee's lion-tamer sports a black bag on his head for most of the film, and Skip Martin mooches about smoking, spying and black-mailing. For its low budget this Hammer fare is tightly plotted, well-scripted and -acted and very entertaining. I bought it to complete my set of Skip Martin DVDs (I understand he appeared in only four films - this, Masque of the Red Death, Vampire Circus and Horror Hospital - and I would recommend them all.) Hammer turned out some unusual and worthwhile films outside of the horror genre. This would be a good place to start exploring them.