Keep It Up Downstairs (movie, 1976)

The year is 1904; the setting is Cockshute Towers, one of England's stateliest homes. When the household is threatened with bankruptcy, both the masters and the servants are prepared to co-operate in trying to find some cash - after all, most of them are enjoying liaisons of one kind or another among themselves, and none have any desire to give up their rewarding way of life...