Does anyone know what could be causing this loud beeping noise? It happens when locking or unlocking the car with the clicker or from the unlock button on the doors.

The sound is coming from under the bonnet. It’s not beeping for doors being open or anything obvious like that. It seems to go away on its own after a random period of time, sometimes up to a few hours, other times fairly quickly but started doing it yesterday at 4pm and is still doing it now. Thanks.