He is expected to leave the bank in October after the firm has appointed a successor. RBS says Whittaker’s current role and responsibilities will continue unchanged until then.
Chief Executive Stephen Hester says: “It is with sadness we reach this parting with Guy and typical of him to agree to serve a full transition period.
“Guy has held one of the most demanding roles at RBS. Since I joined in late November last year, he has given everything to assist our creation of a new direction for RBS and give it the best chance of success.
“Now that we have passed the 2008 year end and are fully focused on the 3-5 year journey ahead to standalone health, it is a logical time to make changes. Guy leaves RBS with my thanks and support and we wish him well in the future once his time here comes to a close.”
Whittaker was appointed to the board in February 2006. He joined RBS after spending 25 years with Citigroup.