A Barclays bank office is seen at Canary Wharf in London, Britain on May 19, 2015. Reuters/Suzanne Plunkett

British lender Barclays surprised markets on Wednesday by announcing a search for a new chief executive in an attempt to accelerate strategic change and boost shareholder returns.

The bank said Antony Jenkins, who has led the bank since 2012, would be stepping aside, leaving its new chairman John McFarlane to take over executive duties until a permanent successor was appointed.

The shock decision came after the board decided new leadership was required to take the bank forward following a period of lackluster results and uncertainty about the bank's future structure.

While lauding Jenkins' role in steering the bank through a period of rapid change over the last three years, Deputy Chairman Michael Rake said the board had decided Jenkins did not have the blend of skills required to take the company forward.

"We are leaving value on the table and a new approach is required. As a Group, if we aspire to bring shareholder returns forward, we need to be much more focused on what is attractive, what we are good at, and where we are good at it," he said in a statement.

"We therefore need to improve revenue, costs and capital performance. We also need to become more externally focused and deal with the internal bureaucracy by becoming leaner and more agile," he added.

The bank said the change of leadership would not equate to a change in strategy at the bank