Martin Lewis explains how much it will cost to keep Christmas tree lights on

If you've been worried about how much your Christmas lights could be bumping up your electricity bill this year, Martin Lewis has revealed exactly how much they could be costing you.

"If you've got LED lights, a string of 100 which is a pretty decent amount, if you were to have them on for six hour a day for the month, it would cost around 18 pence roughly, 18 pence for the month.

"So they are not very expensive to run."

However, Martin also warned Brits that they may not need their lights on for six hours a day.

“Just in the evening when you’re there [at home], so you can keep that element of Christmas going,” he added.

In Martin's Money Saving Expert newsletter, he explained that a 32-metre string of outdoor lights, however, cost a little more to run.

"Bigger sets of lights, with more bulbs, will of course use more energy and therefore cost a bit more – for example, a 32-metre string of outside lights would cost a total of £1.90," he explained.

Speaking about incandescent lights - which are often made of glass and get hot if left on for a while - Martin added: "These tend to be older, and are 80 percent to 90 percent less efficient to run than LED varieties, and so cost much more.

"For example, a 40-watt 100-bulb string of incandescent fairy lights would cost you about £2.45 to run for 30 days over Christmas. Yet some prefer the softer glow these give."

If you are worried about the cost of lights this Christmas, Martin also suggested charging solar lights outside during the day and bringing them in at night.

"You can leave them outside during the day to charge, then bring them inside in the evening. This is harder in winter, when there is less sunlight, so make sure to position them in the best place to get the most sunlight – away from trees, buildings and anything else that may cast a shadow," he added.