Dec 10 Royal Bank of Scotland said its finance director, Nathan Bostock, had resigned after just 10 weeks in the job, dealing a major blow to the state-backed bank's turnaround efforts.
RBS said in a brief statement Bostock had on Tuesday evening told the board his intention to resign and would formally resign soon.
The statement was rushed out after Sky News reported Bostock had quit to join Spanish bank Santander.
Santander declined to immediately comment.
Bostock will join Santander's UK business, which is due to be spun off and separately listed, as chief risk officer and deputy CEO, two people familiar with the matter said.
Bostock was appointed as RBS finance director on Oct. 1.
It is a major blow to new RBS Chief Executive Ross McEwan, who is conducting a review of the bank's strategy and operations, to be released in February.
McEwan has been hit by IT problems which last month caused more than 1 million RBS customers to be left stranded after a computer systems failure.
Bostock was previously head of RBS's restructuring and was expected to play a key role alongside McEwan to create a 38 billion pound ($62.42 billion) internal 'bad bank' announced last month.
Bostock had previously said he planned to leave RBS to join Lloyds Banking Group in 2011, but changed his mind after Antonio Horta-Osorio, the Lloyds chief executive, took a period of sick leave.