If the burner on any of your appliances goes out and the fuel continues to flow
and is ignited this could start a fire or cause an explosion. To reduce the risk of
this happening appliance burners, ignition burners and pilot lights must be fitted
with flame supervision devices that completely and automatically close off the
LPG or fuel oil supply if the flame goes out.

Appliances in good condition and in place before 3 January 2000 are exempt
from this requirement, as long as a flame supervision device is fitted to catalytic
heaters, appliances with a pilot light (e.g. instantaneous water heaters) or those
which normally have a continuous flame (e.g. refrigerators.) [8.5]