The number of plastic bags used by supermarket customers in the UK has risen for the second year in a row, according to new data released by Wrap.

A total of eight billion single-use carrier bags were handed out in the UK last year, up 5.4% on 2010. In Wales, which introduced a 5p levy in October, the number fell by 22%. But shoppers in England used 7.5% more bags and Northern Irish shoppers 8.1% more. There was no significant change in Scotland.

The BRC said the increase reflected changing habits as shoppers did several smaller shops during the week instead of a single larger shop and switched away from using cars to public transport. Both factors meant consumers were less likely to have reusable bags with them, a spokesman said.

It pointed out that the total is a third lower than the 12.2 billion used in 2006, when Wrap began gathering the data.

“Plastic bags account for a fraction of 1% of household waste and the amount of new plastic being used in today’s bags is half what it was in 2006,” said the lobby group’s head of environment, Bob Gordon.

“They have a symbolic status but their impact on the environment is much smaller than other things retailers are turning their firepower on.”

He added: “It’s no surprise the use of a bag charge in Wales has reduced the number of bags taken by consumers there. If other governments see reducing the use of carrier bags as a priority, they will have to take a lead and go beyond voluntary measures.

“Any legislation should be as similar as possible to what’s in place in Wales and we are already working with other governments as they develop their plans.”