The Recovery Position

Even if an unconscious person is breathing, without any blockages, and has a steady heartbeat they may still be in danger. If you leave them lying on their back they may be sick and choke or their tongue may fall back to block their airways. To stop any of this happening you must put the person into the Recovery Position.

Kneel down next to the unconscious person. If they are wearing glasses take them off. Push back the person's head and lift their chin. This will stop their tongue blocking their airways.
Bend the arm next to you so that it is at right angles to the person's body. Bring the other arm across their chest. Hold the back of their hand against their cheek.
Keep holding the person's hand against their cheek and take hold of the leg furthest from you. Pull it up.
Gently pull on the leg to roll the person towards you and onto their side. Don't let the cheek hand slip when you do this.

Once the person is in the recovery position you may leave them for a few minutes to dial 999 for help. When you return, check their breathing. Keep on checking it every 2 - 3 minutes after that, until help arrives.