Households are stockpiling thermal underwear to avoid turning on the heating this winter as energy bills spiral.
John Lewis, Britain's biggest department store chain, said shoppers had rushed to buy warmer clothes in recent weeks, with sales of winter thermals having doubled last week compared to a week earlier. Sales of dressing gowns are up 76pc compared to last year.
Claire Miles, from John Lewis, said: “With the cost of energy such a concern, we are seeing customers spend with heat in mind.”
The spike in sales came as households' energy bills rose last week as the new price cap took effect.
From October 1, the energy price cap rose to £2,500 for an average household per year from £1,971 previously. The cap is on how much energy providers can charge per unit of gas and electricity, and not on how much households can be charged regardless of how much energy they use.
A recent survey commissioned by the Liberal Democrats suggested that almost a quarter of households were planning to not switch on their heating this winter, while 70pc of those surveyed said they would be turning on their heating less.
The International Energy Agency, meanwhile, has called for households to turn down their heating to ward off gas shortages as Russia retaliates over sanctions by cutting supply.
The UK does not get much gas from Russia, but cuts to supply have created more competition in Europe and forced costs higher.
John Lewis said shoppers were buying warmer clothes, even as other retailers said they were expecting people to generally cut back on their spending in the face of steeper household bills.
Earlier this week, Tesco said customers were “watching every penny”, with its sales of general merchandise and clothing down.
Chief executive Ken Murphy said he expected people to be spending less on gifts this Christmas, opting for smaller presents and giving to less people within their friends and family groups.
Boohoo, meanwhile, last week issued a profit warning for the full year, saying “every age group” was affected by inflation. This was prompting a higher level of returns, the company said.