If you have a faulty gas appliance or one that is installed incorrectly, or if your air vent, flue or chimney becomes blocked, carbon monoxide can escape, unnoticed, into your home.

All modern gas appliances need air to burn properly and a flue or chimney to get rid of waste products. If an appliance can't breathe, it won't work properly and the fumes will build up inside your home.

Never install gas appliances by yourself. It is unsafe and illegal for you to do so.

Always arrange for an engineer registered with the CORGI to service and install your appliances.

Make sure all your gas appliances are checked regularly to ensure they are working safely and efficiently. Gas appliances such as fires, cookers, tumble driers, water heaters and central heating boilers need to have a safety check carried out once a year.

Three simple safety checks you can do in your home

• Look for signs of staining, sooting or discolouration on or around your gas boiler, fire and water heater
• Keep vents in doors, walls or windows clear and make sure your chimney isn't blocked with birds' nests or other debris
• Check pilot lights and other gas flames that normally burn blue. If the flame changes to yellow or orange, carbon monoxide might be present

If you notice anything wrong, STOP USING the appliance immediately, open windows and doors to ventilate your home and call the Gas Emergency Services on 0800 111 999 (24hrs). You should also seek medical advice.