They never fail to put a smile on the face of even the biggest Christmas Grinch, but Christmas tree lights can be dangerous.

[Read more: 8 Christmas health hazards: from burns to bad breath]

Perhaps this is one time when more is not merrier, as a house overloaded with fairy lights can be at risk of fire.

Ashley Martin, public health project manager for the Royal Society for the Prevention of Accidents (RoSPA), says: “If you have old lights, seriously consider buying new ones which will meet much higher safety standards.

“Please remember - accidents need not happen, you can protect yourself and your loved ones from injury by following RoSPA's safety advice for a safe Christmas.”

RoSPA has the following advice for enjoying twinkly lights in safety:

What to think about when buying Christmas lights

- Look for safety marks e.g. BS Kitemark.
- Buy from a reputable store.
- Avoid buying second-hand unless you have them professionally checked first.
- New lights are transformed down to 24 volt for added safety, or they may be double insulated.

Christmas lights checklist

- Never insert or remove bulbs when switched on.
- Inspect cables and bulbs for damage.
- Do not use lights which are damaged, dispose of them safely.

What to think about when using Christmas lights

- Read and follow the manufacturer's instructions.
- Use an RCD (residual current device) for added protection against shock.
- Do not use the lights outdoors unless specifically made for such use.
- Don't run the cable under carpets or where it can be damaged.
- Keep lights clear of decorations and other flammable materials.
- Avoid cables becoming a tripping hazard.
- Use a stable support when hanging the lights.
- Don't leave the lights on when the room is empty. Remember to switch them off when you go to bed and when you go out of the house
- Don't allow children to play with the lights.

How to store Christmas lights

- Take care when dismantling and packing the lights not to damage them.
- Keep them safely stored away out of reach of children.
- Avoid damp or excessively hot conditions.