'Circus of Horrors' is one of those fantastically over the top Anglo-Amalgated horror films that so disgusted the Establishment and titillated audiences in the late fifties and early sixties with their relentless sex, perversity and sadism. This one is about an insane plastic surgeon who uses the anonymity and mobility of a big top show to continue his (actually pretty successful) experiments, pausing now and again to knock off people who might blow his cover.
Fifty years on, it's more circus than horrors, more schlock than shock, although the acts (supplied, of course, by Billy Smart) are excellent, there are some very attractive ladies, an enjoyably manic performance from Anton Diffring and an interesting shared subtext with 'Peeping Tom' (another Anglo release in the same year) - that hideous disfigurement can be a bit of a turn on.
Here's the trailer. Sadly it doesn't really feature the stuffed bear that sees off Donald Pleasence, or indeed the man in a gorilla suit who causes a lot of problems for Anton Diffring, but don't let that put you off - it's very informative in all other respects.