The Satanic Rites of Dracula (1978)

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.