Barclays has confirmed that Bob Diamond, head of its investment banking arm, Barclays Capital, will take over as chief executive when John Varley steps down at the end of March next year.One of the City's best-paid bankers, Diamond has been running the division since 1997 when it was Barclays de Zoete Wedd (BZW). He becomes president and deputy group chief executive at the beginning of next month.It's a money-spinning move for the 59-year-old American. His basic salary rises to £1.35m a year plus another £3.4m in bonuses and £6.75m in long term, performance-based share incentives.Business Secretary Vince Cable may not approve of the appointment. He's already condemned the investment banking industry as "casino banking" and he'll remember that Diamond earned £21m in 2007 and, although he waived this year's payout, took home a bonus of £22m in June 2009 following the sale of Barclays Global Investors to Blackrock.Varley, boss of the high street bank since 2004 and the man who helped Barclays survive the financial crisis, won't leave the company until 30 September 2011, staying on to advise on regulatory matters. He spoke very highly of his successor today: "I am delighted that the board has appointed Bob as my successor. What he has accomplished in his various roles at Barclays demonstrates clearly that he is a great banker and leader, and an outstanding business builder; I know that Barclays will flourish under his stewardship."Diamond spent many years working for Morgan Stanley and Credit Suisse First Boston before starting his Barclays career. He eventually joined the board in 2005.The Chelsea fan promised a "seamless transition" and said he faced the future with confidence.His role at Barclays Capital will be shared by Jerry del Missier and Rich Ricci, who'll become co-chief executives from 1 October, as well as being co-CEOs of the Corporate and Investment Bank.