There's a simple way of calling the police if you find yourself in trouble, but it's unsafe to talk.
Police have issued a reminder about what to do in a situation in which you're able to dial 999, but unable to tell the operator you need help.
The correct procedure to follow, which is called Silent Solutions, decides whether to dispatch police to thousands of silent callers every day – but not everyone knows what to do.
You're probably aware that when you phone 999 (or 112), the operator will ask what emergency service you need. If there's no request, the assistant will ask you to 'cough', or make some other audible indication in the case of a police emergency.
If even making any sound is dangerous, and therefore no request is made, the call will be put through to an automated system, which asks the caller to press '55' if they're in trouble.
If no sound is made and '55' isn't dialled, the police will not attend, the Express and Echo explains.
A police spokesman said: "Please do not think that just because you dial 999 that police will attend.
"We totally understand that sometimes people are unable or too afraid to talk, however it must be clear that we will not routinely attend a silent 999 call.
"There must be some indication that the call has not been mis-dialled."
In November last year, a woman murdered by her ex-partner was "absolutely let down" by the police, her mum has said, as watchdogs call for a review of the 'silent' 999 call system.
Kerry's body was found by her ten-year-old son Ollie on the morning of December 14, 2013 at their home in Tailyour Road, Crownhill, the Plymouth Herald reported .
