Royal Bank of Scotland has come under attack for warning its staff they faced disciplinary action if they did not open a company bank account.
The Amicus union said it had been "jammed with calls from angry staff" after the NatWest and Churchill owner sent a letter warning workers of the consequences of not having a company current account to receive their salary.
Amicus said the approach of the UK's second biggest bank had been "disproportionate and heavy-handed", adding that it was impacting on staff morale. It said it was seeking legal advice on the matter.
RBS chief executive Sir Fred Goodwin said the letters had been sent as a result of "tidying up" within the company to remind a "few hundred" staff of their contractual obligations. "It has been a long standing requirement of people's employment," he said.
RBS did not provide further details of why it felt it was necessary to pay staff wages into an RBS current account.
The letter from Gordon Pell, chief executive of retail markets - the group's consumer banking division - said: "I must therefore ask you to open an RBS Group bank account. Failure to do so will represent a breach of group policy and I will be obliged to write directly to your line manager asking them to progress this matter to the group's disciplinary policy."
Amicus claimed the letter had been sent to about 14,000 staff, including staff transferred into the group after the acquisitions of Direct Line and Churchill Insurance and the merger with NatWest.
However, RBS said that no members of staff in its insurance division had yet received a letter, saying that it had been sent from the banking division and had gone to staff in branches who deal with the public regarding RBS Group bank accounts.
Amicus' Alison Maclean said: "Whilst it is desirable for employees to hold a bank account with the organisation for which they work, if they work in the financial services sector, it is not something the union would view as essential.
"We believe that the employer's approach in this has been heavy-handed and certainly not conducive to good employee relations. We are talking about employees who have been loyal to the bank and dedicated and never had any issues in terms of proposed disciplinary action and they now find themselves in a situation where potentially they could face disciplinary action for failing to have their salary paid into a group bank."
