The horn is an important control on any vehicle. The horn must be working correctly as part of the MOT requirements.
The purpose of the horn is to warn others of your presence or immediate danger.
Using the horn in an aggressive manner or even to inform ‘friends’ of your arrival at a location can be dangerous by causing a distraction or cause alarm to other road users.
The use of the horn in built-up areas, unless there is immediate danger from another vehicle is restricted at night to between 11:30 pm and 7:00 am.