Mistress Pamela

Mistress Pamela is a 1973 British sex comedy drama film directed by Jim O'Connolly and starring Ann Michelle, Dudley Foster, Anna Quayle and Anthony Sharp. It was loosely based on the 1740 novel "Pamela, or Virtue Rewarded" by Samuel Richardson.
Plot.
In the eighteenth century, Pamela, a servant girl in the household of Lord Devenish, must fight off the advances of her young master - a gentleman determined to have Pamela as his mistress.
Critical reception.
"Time Out" wrote, "Richardson's 18th century classic Pamela clearly dredged up for its bawdy possibilities...About all the film has in common with the original is a notable lack of humour."