Morris Minor Owners Club

Hi, i have a morri thousand factory convertible and used my horn a couple of days ago and it has been stuck on ever since. managed to disconnect it using the wiring diagram in haynes, but the button in the steering column seems ok and i am not sure what next. everything else is working fine.
thanks

The horn button provides the earth for the circuit. Either something is adrift in the button or a chafed wire is earthing.