We appreciate that there are some people who find it hard to stay warm in the cold winter months and with the cost of living putting pressure on some households, we wanted to take a look at some thermal underwear this week. So Sophia Smith has a 7 Day Challenge for us and for Day 4 we are back with Marks and Spencer to try on their thermal heatgen leggings 2-pack. Come back tomorrow for Day 5 of her challenge and at the end of the week she'll conclude with picking the best from all 7 items reviewed. Filmed in 4K.

"They did have many colour options, so many. There was a rainbow of options!" Sophia Smith