In about early 90's I watched a British black comedy where a number of old people are living in an old house, and due to a range of coincidences, they all end up dead. Does anyone know what this movie is?

You said you watched it in the 90's, is the movie itself from the 90's or earlier? If earlier, my first thought was the original version of the LadyKillers...
The Ladykillers - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/The_Ladykillers)

Thanks for the suggestion - sounds like a great movie but sadly not the one I'm thinking of. It could have been slightly earlier or later but set around that time. It was one of those unfanfared British movies (probably made for TV) that is an enjoyable surprise. Very much in the vein of 'Keeping mum' and 'Cold comfort farm'.