Royal Bank of Scotland has appointed Ulster Bank's CEO Jim Brown as the new chief executive of its Williams & Glyn business.
The bank said that Mr Brown will remain in his position at Ulster Bank to help the bank's board find his successor.
Williams & Glyn business is due to become a new UK "challenger" bank.
RBS was ordered to sell Williams & Glyn, which comprises 314 branches and is focused on lending to small businesses, by European regulators as a condition of its £46 billion government bailout during the 2007-09 financial crisis.
It plans to list the business on the London Stock Exchange in the second half of 2016.
"Jim Brown brings a wealth of experience in retail and commercial banking and will lead the business as we move forward towards an IPO in the second half of 2016," commented the CEO of RBS Ross McEwan.
From New Zealand, Mr Brown joined Ulster Bank in April 2011. He has seen the bank return to profitability and steered it through a strategic review that saw RBS recommit to Ulster Bank last year.
In February, the bank reported an operating profit of €752m for the year to the end of December 2014 - its first annual profit since 2008.
Its parent RBS had pumped £15 billion Ulster Bank since the crash in 2008.
John Maltby, previously head of commercial banking at Lloyds, became chief executive of Williams & Glyn in January last year.
He had been expected to lead the business through its stock market flotation, with the intention of subsequently building it into a significant rival to Britain's biggest banks.
Sources said the decision to change Williams & Glyn's leadership had been made jointly by RBS and the investor consortium, which also includes the Church of England.
Meanwhile, Mr Brown and Bank of Ireland boss Richie Boucher will appear before the Oireachtas Joint Committee on Finance, Public Expenditure and Reform in separate sessions tomorrow as part of a series of meetings on the Irish banking sector.
