The Press Association has learned that the lender, still 62% owned by the Government, paid individuals £330 day plus VAT to carry out mundane tasks such as sending PPI letters to customers.
The hefty sums were paid during certain periods in 2017 and this year at an office in Manchester.
Those working on the project told PA that they were originally hired to work as specialists, but were then told to put letters in envelopes because of management disorganisation.
“It is purely because they have no organisational skills on the project we were on and was a complete waste of taxpayers’ money,” said one contractor who worked on the project, speaking on condition of anonymity.
Typical envelope-stuffing jobs are paid at the minimum wage, meaning taxpayers have lost out to the tune of thousands of pounds, although the exact figure is unknown as RBS has not disclosed the total number of people receiving the bumper pay rate.
The damning revelations will come as a major embarrassment to RBS chief executive Ross McEwan, who has pledged to cut costs at the lender and stamp out scandals under his watch.
In its defence of the bumper wage, RBS said in a statement: “We do not hire contractors at this rate to do this type of work. When we employ contractors, they are paid in line with industry rates according to their experience and skills.
“There have been a limited number of occasions when we have used short-term support from other areas of our business to ensure we are delivering on time and in line with our commitments for our customers.”
Since the financial crisis, RBS has been dogged by furore surrounding the mis-selling of payment protection insurance (PPI), mortgage-backed securities and the mistreatment of small businesses.
In addition, Mr McEwan has taken an axe to the RBS branch network as part of cost-cutting measures, resulting in hundreds of job losses.
RBS has made more than £50 billion of losses since it was handed a £45 billion state bailout at the height of the financial crisis in 2008.