When a pipe bursts, turn the water off at the inside stop tap first, turning it clockwise. It is usually under the kitchen sink, but can be in a downstairs toilet, a garage, a cellar or under the stairs. Turn it slowly and never force it, as too much force can damage it.
If water may have reached the electrics, switch the power off at the fuse box and do not touch sockets or wiring that may be wet. Then look up. A bulging ceiling means water is pooling above it, so keep everyone clear in case it comes down.
With the stop tap off, flush the toilets and open the cold taps over sinks and baths to drain the water left in the pipes. Turn off the central heating and any immersion heater, so nothing heats while the system is empty. Soak up what you can with towels or buckets, and move furniture and belongings away from the wet area.
The sooner the water is off, the less there is to soak up, so find your stop tap before you need it and check it works every six months. If it will not turn, or once the water is off, call me and keep it off until I arrive. I run G R Plumbing and repair burst pipes across Caterham, and you can see more of my plumbing work here.
