Just recently for no apparent reason our toilet cistern in the bathroom keeps filling quite frequently when the toilet has not been used and flushed.

David Yule, December 2007

Simple - the float valve washer has failed and it needs to be replaced. All types of washer are available but the easy way is to replace the whole valve as a unit - depending on what type and make it is. Often there is so much limescale on these things that they don't like coming undone.

John, December 2007