What causes a burst pipe, and what should I do the moment I notice one?
Freezing, age and pressure are the usual causes - the moment you notice a burst, isolate the water at the stopcock and treat any water near electrics as a reason for extra caution.
Cold snaps are a common trigger, since water expands as it freezes and can split a pipe from the inside - the failure often only becomes obvious once the ice thaws and water starts flowing again. Older pipework is also more prone to failure through age and corrosion, and consistently high pressure can accelerate wear on joints and weaker sections over time. Whatever the cause, speed matters most once it's happened: the sooner the stopcock is turned off, the less damage accumulates, and any burst anywhere near sockets, switches or a fuse board is a reason for extra caution around electrics too. See our emergency plumber page for the fuller picture on what to do while waiting for help.