Mr James said there had been a “huge shift” over the past two years towards automation, which had harmed customer service across the board.

“There are thousands of complaints every week mentioning chatbots, ineffective live chat functions and online forms that are hard to locate,” he said. “What’s clear from the complaints I see is that customer service is going backwards and people are palpably angry about it.”

Brands said they were battling high levels of staff absence.

British Gas said: “Our 7,000-strong workforce of highly skilled engineers visited over five million homes last year. However, Covid has had a significant impact as we have experienced higher absence rates during the pandemic. Absence rates more than doubled in 2021.”

It added: “We need to protect our employees and customers and clearly our engineers can’t go into a customer’s home if there is a risk of spreading the virus. Unfortunately this has led to jobs being rescheduled and this means we let down some customers.”

A BT spokesman said its complaint numbers were below both the industry average and pre-pandemic levels.

Mr James said firms risked losing customers forever because of poor service. “It’s foolish to assume that the British public will just put up with poor service – and some brands risk damaging their reputations past the point of no return if they don’t invest in communicating and listening to the people who use their services,” he said.

Government organisations were also criticised for their poor service in the Consumer Intelligence poll. 

Some 7pc of those surveyed said both HMRC and the DVLA had used Covid as an excuse for poor customer service this year.

Last year HMRC scrapped phone waiting time targets after service levels plummeted. Experts at the time blamed its working-from-home policy.

Meanwhile, industrial action at the DVLA led to a backlog of paper licence applications last year. The Swansea-based agency is following Welsh Government advice, which has been more restrictive than English rules.

Jo Causon of the Institute of Customer Service said: “Covid-related issues have resulted in difficulties delivering a consistent service; however, the last two years have enabled organisations to explore new ways of serving customers. 

“We are seeing a divergence between those who have invested sufficiently in their people and technology, and those who have not.”

Ms Causon said research had shown that increasing numbers of people were happy to pay more to firms that offered better customer service.

“Avoiding blanket statements about Covid-related problems and having clear, upfront and honest communications is critical,” she said.

A HMRC spokesman said: “We’re making solid progress during a year of recovery, reducing the average time taken to answer calls by around 10 minutes since April, down to nine minutes in December, and overall customer satisfaction has remained above 80pc throughout 2021-22.”

A DVLA spokesman said: “We have followed Welsh Government guidance to keep staff safe and will continue to do so. We have recruited more staff, have increased overtime and opened new customer service centres in Swansea and Birmingham to help reduce waiting times.”

Barclays, TalkTalk and HSBC did not respond to requests for comment. Sky and Virgin Media declined to comment.