The push button for the toilet cistern is on the top (the lid) the cistern is constantly filling so either there is a leak into the bowl or a seal needs replacing. I can't work out how to get the top off to have a look. Its a Villeroy and Bosh cistern

Sue Graham, March 2011

Usually you unscrew the outer ring around the button,it will only be finger tight.I would first check the float height before messing around there will be a mark inside the cistern for the level just screw the float down a bit.Don't presume until you have a look.

Rich, March 2011