EDINBURGH (Reuters) - Royal Bank of Scotland's RBS.L finance chief quit unexpectedly on Wednesday and cast doubt on the timing of a possible sale of some of the British government's controlling stake.

FILE PHOTO: sign is displayed outside of a branch of The Royal Bank of Scotland in central London, Britain May 20, 2015. REUTERS/Neil Hall/File Photo

Former investment banker Ewen Stevenson declined to say where he was going or exactly when at the bank’s AGM.

“You’ll know when there is news to tell,” he told reporters at RBS’ headquarters in Edinburgh, where the meeting was held, while RBS said a leaving date would be confirmed in due course.

Asked about reports the government could start selling down its more than 70 percent RBS stake this week, Stevenson said a sell-off in bank stocks sparked by nervousness over political developments in Italy and Spain made this unlikely.

“I’d be surprised if now was an optimal time to sell,” the 52-year-old New Zealander who became CFO in 2014, said.

RBS was rescued in a 45.5 billion pound ($60 billion) bailout by the British government during the 2008 financial crisis and has spent the last decade shedding trillions of dollars of assets and dealing with the legal and regulatory hangover from an unfettered pre-2008 global expansion.

Stevenson joined RBS in May 2014 after 25 years at Credit Suisse CSGN.S and has led turnaround efforts with the bank's chief executive Ross McEwan, who arrived six months earlier.

McEwan, who has dismissed speculation about his own departure, told reporters at the AGM he had only heard of Stevenson’s plan to depart in the last 24 hours.

“I’m sad to lose Ewen, he’s done a fantastic job,” McEwan, a fellow New Zealander said.

The bank’s shares, which have gained around 2.8 percent since the bank’s full-year results in February, were down 1.4 percent to 276 pence at 1415 GMT.

GOGARBURN

The top ranks of RBS have come under scrutiny since the conclusion of a U.S. Department of Justice probe which resulted in a $4.9 billion settlement over the mis-selling of mortgage backed securities.

Shareholders have raised questions about who will be best placed to lead the bank through its next phase of recovery and the long awaited transfer back to full private ownership, with speculation centered on the future of McEwan.

At its Gogarburn complex on the outskirts of Edinburgh, a sprawling campus of offices and shops built on the site of a former psychiatric hospital, McEwan defended branch closures, saying they were needed to address declining customer visits.

While RBS has since turned over much of the site to local businesses in a bid to draw a line under that era of excess, the bank still faces criticism in Scotland for the rate at which it has been shuttering branches.

Outside the complex, which was opened in 2005 at a reported cost of 350 million pounds, protesters from the union Unite gathered ahead of the meeting to protest at the closures.

At the bank’s site in Manchester, Unite said another protest drew around 50-60 demonstrators.

(This version of the story refiles to remove extraneous word in para 11.)