Hi , if there was an emergency water leak or I needed to have plumbing work completed and the water supply needed to be turned off from the mains I’m not able to do this or how do I do this please ? There isn’t a stop clock in the house . Outside my property I’m unable to turn the supply off as it doesn’t seem to turn and looks lukewarm it will snap . I bought a tool to be able to turn it off however it doesn’t work . I have attached a photo . Please would I be able to get some help with what to do .