Signaling a return to its British banking roots, Barclays has appointed Antony Jenkins, an insider, as chief executive, as the institution aims to restore its reputation after a rate-manipulation scandal.

Jenkins, an Oxford-educated Briton who led the retail and business banking unit, steps into the top spot during a period of continued upheaval for the bank.

Barclays is trying to distance itself from the rate-manipulation scandal that occurred under chief executive Robert E. Diamond Jr., who resigned in July.

Analysts and bank employees have said Jenkins would be a good fit for the job, citing his genial style and focus on consumer banking.

The bank faces questions about its capital-raising efforts in 2008. On Wednesday, Barclays said that Britain’s Serious Fraud Office had opened an inquiry, following a similar one by the Financial Services Authority.

Jenkins, 51, acknowledged the challenges ahead, saying the bank had ‘‘made serious mistakes in recent years and clearly failed to keep pace with our stakeholders’ expectations.’’

The US Justice Department is also investigating Barclays traders as part of the broad Libor case and could bring criminal charges.