The struggling UK retail sector may not get the Christmas sales boost it desires, as new research shows many customers did the majority of their festive shopping during the Black Friday sales.

New research by Retail Economics and Klarna found more than a fifth of customers said they bought Christmas gifts during Black Friday in an effort to take advantage of widespread discounting.

The survey found customers, on average, spent £179 on gifts during Black Friday, which Retail Economics said was almost 40% of an average household Christmas budget.

The research estimated that customer spent £2.1bn overall on Christmas gifts during Black Friday, around 16% of the total festive spending during what is already a heavily discounted period.

While the findings could come as a blow to the UK retail sector that is holding out for a strong Christmas after a year marked with political uncertainty, softening consumer confidence and prolonged discounting, the survey found the damage was not as bad as it could have been.

Around 28% of customers surveyed before Black Friday said they would use the discounting period to buy Christmas gifts, but only 22% of respondents said they actually did so.

However, Retail Economics said that consumer confidence remains soft coming up to the crucial festive period, with 38% of customers planning on spending less this year than last, compared with just 16% who said they would be spending more.

The data showed Black Friday spending this year was focused on fewer categories and was increasingly migrating online. Electricals saw 43% of purchases, apparel 42% and games 29%.

Retail Economics chief executive Richard Lim said: “The later timing of Black Friday proved much more disruptive for retailers as payday arrived in time to spur on spending.

“The big question retailers are asking themselves is whether the Black Friday boost will be a worthwhile price to pay if shoppers just pulled forward spending at the expense of Christmas sales.

“This is likely to be the case for many retailers and those that didn’t take part in the event at all may have to pay the price through heavy discounting post-Christmas.

“A successful Christmas period hangs in the balance for the industry as ongoing political and economic uncertainty plagues consumer confidence. Although almost two in five consumers expect to spend less this Christmas than last year, a decisive election result may give the industry some festive cheer.”