Evil begets evil on the sabbath of the undead!

The Satanic Rites of Dracula (1973)

Directed by Alan Gibson

The police and British security forces call in Professor Van Helsing to help them investigate Satanic ritual which has been occurring in a large country house, and which has been attended by a government minister, an eminent scientist and secret service chief. The owner of the house is a mysterious property tycoon who is found to be behind a sinister plot involving a deadly plague. It is in fact Dracula who, sick of his interminable existence, has decided that he must end it all in the only possible way- by destroying every last potential victim.