RBS Executive Chairman of CIB to Leave Firm

The news comes a month after Cullinan was promoted, and is due to disagreements with senior management regarding the strategy of the bank, according to a Financial Times report.

"We would like to express our thanks to Rory for his very significant contribution to the rebuild of RBS over the past six years," said Ross McEwan, RBS CEO, in a statement. "He has built and led APS, Non-Core, RCR and recently completed the very successful follow-on sale of Citizens post its IPO last year. We wish him every success in the future."

Cullinan was to play a significant role in RBS shrinking its investment banking arm, which it announced it planned to do in February. Chris Marks, CEO of CIB, and Mark Bailie, CEO of Capital Resolution, will join the bank's executive committee as co-CEOs of CIB.

Earlier this month Cullinan drew criticism when selfies he sent to his daughter via Snapchat with captions, "Not a fan of board meetings xx," "Boring meeting xx," and, "Another friggin meeting," were published in the British tabloid The Sun.

According to the FT story, Cullinan's departure stemmed from arguments with senior management over how to begin the strategy the bank had drawn up regarding downsizing its institutional arm when Cullinan took over.

"I am pleased and proud to have played a significant part in restoring RBS to a safe and sound agenda over the past six years," said Cullinan in a statement. "I wish all my colleagues continued success."