Answer

By Trail magazine

The standard procedure is for walkers to carry a whistle and a torch and use the emergency signal of 6 blasts of the whistle or 6 flashes of the torch to attract attention. If these two systems are used then often that will be enough to attract attention.

Most people also carry a mobile phone and these can be ideal for calling for help by dialing 999 and directing the rescue teams to your location. If you are carrying a rope, extend that from your position so rescue teams on land can find you more easily. You could even arrange rocks into a a big arrow on the ground to literally point rescue teams in the right direction.

However, if you are walking alone attracting attention may be more difficult, especially if you have fallen into a ravine, are hidden by undergrowth and unable to move, or find there's no mobile signal. In these situations flares would be useful and some walkers and climbers do carry them.

I don't think they're essential for every walker, but if you're heading into remote terrain, particularly alone or in a small group, they can be a useful addition.