Quick answer
Check the consumer unit for a tripped MCB. If the circuit is on but the socket is dead, the socket itself has failed or there is a wiring fault.
When a socket stops working, start at the consumer unit. Find the switch labelled for the affected room or circuit — if it is in the down position it has tripped. Switch it off, then back on. If it trips again, there is a fault on that circuit — call an electrician. If the MCB is on but the socket is still dead, try plugging a lamp or phone charger into nearby sockets to see if they work. If all sockets in a room are dead but the MCB is on, there may be a fault in a fused spur or junction box. If just one socket is dead, the socket itself may have failed — do not try to open and fix it yourself. Call a qualified electrician to replace it.
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