external stopcock

[greenforehead]

Hi all, new so go easy! I have no internal stopcock. I can reach the external one but have no idea what I'm doing. it has a round blue plactic cap and a white plastic valve. I assumed i simply turn the valve clockwise to shut it off but it seems to turn endlessly in both directions. What am i doing wrong?

[petetheleak]

Should be just a quarter turn ,But seeing as it could now be either half open or half shut [depending on how your mind works].Turn on your kitchen tap and turn valve a wee bit at a time untill hey presto water should stop if its your valve that is .But a would get an internal valve fitted as soon as .Failing all that give the water board a call and tell em you have an uncontrolled leak in your house.