Minor flood - Check your overflows ! ! ! Answered
Just had a minor disaster here - Water dribbling through from the roof into the airing cupboard because the float valve on the hot water tank had stuck and the overflow pipe to the outside was blocked. Rapid turning on of hot tap and leaning suicidally out of the window with a length of stiff copper wire to unblock the pipe averted a worse situation.
The overflow appeared to be blocked with mud, and this is not the first time it happened. Some years ago this happened in daylight and I could see the pipe was also full of mud and small pieces of stick. I suspect that some insect - possibly a bee - had been nesting there. Order of the day tomorrow is to put a one-way flap type arrangement over the overflow to stop it happening again.
But this has also reminded me it's time to make some safer accommodation for bees, ladybirds etc for overwintering. I'll be knocking up something like THIS tomorrow and maybe they'll leave my plumbing alone!