What should I do if my roof is leaking?

The order matters, because the first ten minutes do more to limit the damage than the next two hours.

Electrics first. Water tracks along cables and collects in ceiling roses and downlight housings, and a wet downlight is a live conductor above your head. If water is anywhere near a light fitting or a socket, switch that circuit off at the consumer unit and leave it off. Do not switch the light on to check, and do not stand in water to reach it.

Then the ceiling. Wet plasterboard holds a serious weight and lets go all at once. If you can see a bulge or a sagging patch, put a container underneath and pierce the lowest point of it with a screwdriver. It feels like the wrong thing to do and it is the right thing to do — a controlled release into a bucket is far better than several litres arriving with the ceiling attached.

Then contain and record. Buckets down, furniture moved, carpet lifted if it comes up easily. Photograph the water, the ceiling and — from the ground — anything visibly wrong on the roof. Insurers settle claims that come with evidence taken on the day.

Do not go up on the roof, and do not put a ladder up in bad weather. Wet slates are lethal underfoot, a roof that has lost fixings will not take weight where it used to, and this is the single commonest way a roof problem turns into a hospital visit. Anything worth seeing can be seen from the ground with a phone camera.

One thing worth ruling out before assuming the worst: in heavy rain a blocked or overflowing gutter can push water back under the eaves and into the roof space, which produces exactly the symptoms of a roof leak and is fixed with an hour's work rather than a scaffold.