Nobby
J's advice is good to go but are you sure you don't have a fault on the circuit that is supplied by the MCB?
If you are able I would check thet the circuit is good before replacing stuff, Try removing all all items plugged into the circuit and resetting or if its a lighting circuit remove all lamps and switch off the lights. Appliance circuits should have the fuses at the wall switch removed. Of course this all depends on which type of circuit is covered and won't check against cable damage.... Any recent DIY picture hanging drilling etc?
Don't be tempted to put a bigger or different rated MCB in its place stay away from the big retailers and buy the MCB from an electrical wholesaler who will make sure you get a domestic rated mcb with a good name
Hope this helps
Kennyf
Kennyf
March 2009