The Unite union attacked Barclays' "reckless rush" to close branches yesterday, warning would be unpopular with customers.

Barclays denied it was planning a significant reduction to its branch network, amid speculation that up to a quarter of its 1,600 sites in Britain could close.

However the bank admitted there will be fewer traditional branches in the future.

According to the Financial Times, the bank is planning to replace around 400 branches with smaller sites in Asda supermarkets.

Unite national officer Dominic Hook said: "Barclays must not embark on this reckless rush to close branches and fill others with machines instead of staff.

"There will be a significant cost to customer service in Barclays. Unite has called on Barclays to halt its bank branch closure plan.

"The banking industry must step back from the rush to install banking machines across all their branches at the continued expense of employment and training of a much-valued workforce."

The union published a survey earlier this week which showed public opposition to automation in bank branches, with consumers preferring to deal with staff rather than machines.

Mr Hook explained: "Research shows the significant reputational damage the banks will suffer if they ignore the needs of their customers.

"With 72 per cent stating they have had problems with machines in branches and 62 per cent preferring more staff in branches, there is no doubt about the importance of frontline bank staff.

"Barclays customers don't want to see empty soulless branches. There are serious questions as to what this reduction in staff numbers will do to customer service in Barclays."

A Barclays spokesman said: "We have consistently been clear that, over time, there will be fewer traditional branches as we move to provide banking services to customers where and when they find it most convenient.

"While it is inevitable that there will be speculation about how these changes will impact on the branch network, this will be driven by the needs of our customers and, therefore, there is not a target for a number of branches to be closed, nor a timeframe for such action."

Speculation over Barclays' branches follows an announcement yesterday by Lloyds Banking Group of 1,080 job losses across its retail, risk, operations and commercial banking divisions.