A stopcock key is a valuable tool to have but it is normally not appreciated until you try and isolate the water supply underneath the sink and find that you cannot isolate it due to a seized stopcock. As the outside stopcock is about 2 feet 6 inches below floor level you can of course put your arm down and turn the stopcock by hand but you never know what is down there. Rat's urine which carries weil's disease ( a potentially deadly illness caused by bacteria which is passed to humans in contact with diseased animals) could be present or broken glass, personally I never put my arm in any hole where I cannot see it! So I do not advise you to do so either.

A stop cock key would normally look similar to this one but can be easily made from some off cuts of wood

All you need is about a 1 metre length of 2 inch by 1 inch timber (slate batten is fine) and a piece of 2 inch by 1 inch timber 12 inches long and a couple of 11/2 inch screws or nails.

Cut a Notch out of one end of the 1 metre long piece of timber as shown above. The Notch needs to be about half of a inch wide by 2 inches deep

Fasten the short length of wood to the Long piece using either screws or nails and your stopcock key is ready to use.