(Reuters) - Britain's Royal Bank of Scotland will pay U.S. and British authorities $615 million and plead guilty to wire fraud in Japan to settle allegations it manipulated global benchmark interest rates.

"The RBS board acknowledges that there were serious shortcomings in our systems and controls and also in the integrity of a small group of our employees," Chairman Philip Hampton said on Wednesday.

"This is a sad day for RBS, but also an important one in continuing to put right the mistakes of the past."