A new survey from USwitch shows one in six customers avoid topping prepayment meters up because they can't afford to.

A survey carried out by USwitch and YouGov shows 15% of prepayment meter customers have avoided using energy for two days or more this winter because they cannot afford to top up — up by a third 36% compared to this time last year.

Around 4.5 million energy customers use prepayment meters for their energy, paying £97.40 a month on average.

Prepayment energy prices tend to be higher, owing to the extra cost of running the infrastructure, meaning prepayment customers typically pay more for their energy than those on a fixed deal with a standard meter, who pay £92.70 a month on average.

People on prepayment meters currently pay £56.40 more than those on fixed tariffs over the course of a year

The new findings suggest the increase in the cost of living is already having an impact, the firm says, with many prepayment meter customers already struggling with their energy bills, even before the energy price cap rises in April by £708 from £1,309 to £2,017.

Prepayment meter customers say topping up their meter with £10 a year ago would buy enough energy to last an average of 5.8 days, USwitch says. £10 now lasts just 4.4 days, meaning people now need to top up seven times a month on average, versus five previously.

A fifth of those with prepayment meters said they have skipped hot meals because they cannot afford to top up, an increase of almost a quarter) on the proportion who did so at this time last year, the survey says.

Other findings from the research show more than a third (35%) say they have worn a coat, hat and gloves indoors to fend off the cold rather than putting the heating on, while nearly a fifth (19%) have sat in the dark to avoid using energy.

One in 10 (10%) of people have also not been able to make an important call because they ran out of battery on their mobile phone while avoiding charging in order to save energy.

Nearly a sixth (13%) of those on prepayment meters say they want to move to a traditional meter instead while 16% of people who have either not tried to move to a credit meter, or were not successful in switching over, did not realise it was even possible to move.

Of those who have considered switching to a traditional meter, 13% said their landlord had or would prevent them from doing so, while one in 10 (12%) are confused by the process.

Meanwhile, 7% of people who tried to move were prevented from doing so because their supplier said they were in too much debt, while 6% could not afford to pay the upfront cost of a deposit for a new meter and 5% failed a credit check.

Jean Hayes, community engagement lead at USwitch, said: "The upcoming increase in the energy price cap is going to be challenging for everyone, but people on prepayment meters are set to be hit hardest.

"Prepayment customers are often the most financially vulnerable, and our research suggests some are already being forced to make a tough choice between heating and eating.

"As the rapidly rising cost of living eats into many households’ budgets, it’s alarming to see that a sixth of people with prepayment meters have already felt compelled to avoid using their electricity for days at a time this year - and this is before the new energy price cap even takes effect.

"Prepayment meters often make energy more expensive than standard credit meters, so anyone who is finding it unaffordable should speak to their supplier and see if moving to a standard meter could be an option for them."