Williams & Glyn, the challenger bank being carved out from RBS as a condition of the latter's bailout during the financial crisis, has lost its chief executive before it has even launched.
John Maltby will be replaced by Jim Brown, currently chief executive of Ulster Bank.
Maltby will take up his former role as adviser to the consortium of external investors who took part in a £600m bond issue in 2013, which led to the creation of the new bank.
Williams & Glyn was last on the high street 30 years ago. It is expected to launch through an IPO next year when RBS' branches in England and Wales and NatWest's Scottish branches will transfer over to the new brand.
RBS chief executive Ross McEwan said: "I would like to express our thanks to John Maltby for his very significant contribution to Williams & Glyn over the past 18 months.
“Much has already been done in building a standalone business and we are grateful for the important role that John has played in getting the bank to this point.”
Lord Mervyn Davies, who represents the external investors' consortium, said: "The delivery of a new challenger bank is an exciting proposition and we look forward to working with Jim through this next stage to IPO."