They take fire seriously with listed buildings

I woke up to some very loud vehicle noises from the street, which went on for at least 20 minutes, so I opened the shutters and saw - 4 firetrucks. They had arrived without sirens (8.30 AM on a Sunday) and this picture was taken about five minutes before they drove away.

False alarm or very small fire? In any case, I feel safe knowing they'll send out four appliances if I burn my toast on a Sunday morning ;-)