Washing machine won't start — likely causes and safe checks (UK)

A machine that won't start usually has a door-lock, power or control-panel issue — all three are worth checking before booking a repair.

Likely causes, ranked

Door not fully closed or lock faulty Most likely — The programme will not start unless the lock is detected as closed.
No power to the machine Likely — Check the socket with another appliance; check the fuse in the plug.
Child lock active Likely — Many models have a child lock that stops all buttons working — check the manual for the button combination.
Control board fault Less likely — If power and door are fine but the panel is dead, the board or its wiring is at fault.

Unplug before checking the plug fuse. If the machine trips the RCD in the consumer unit, stop and call an electrician — do not reset repeatedly.

Call a professional if the machine trips the electrics, or if the panel stays dead with confirmed power and an unlocked door.