Limit the damage inside
Put a bucket or bowl under the drip and move furniture, electricals and valuables out of the way. If water is near light fittings, switch the circuit off at the fuse box.
If you can safely get into the loft, put a container under the leak and lay something down to protect the ceiling. Never go onto the roof yourself.
Common causes of roof leaks
Slipped or broken tiles and slates, cracked ridge mortar, lifted lead flashing around chimneys, blocked valleys and gutters, and splits in flat roof coverings are the most common causes we find.
Water often travels before it drips, so the stain on your ceiling isn't always directly under the problem.
When to call a roofer
As soon as possible. A small leak left alone can rot timbers and damage ceilings and insulation, turning a simple repair into a much bigger job.