The British Serious Fraud Office has charged Barclays and four of the bank’s former executives with conspiracy to commit fraud. The charges come after a five-year investigation into the London-based lender’s fund-raising at the height of the 2008 financial crisis.

The accused are John S. Varley, a former chief executive; Roger A. Jenkins, a former chairman of investment banking for the Middle East; Richard W. Boath, a former head of investment banking; and Thomas L. Kalaris, a former head of the bank’s wealth division. Barclays and Mr. Varley and Mr. Jenkins were also charged with providing unlawful financial assistance.

Barclays had raised nearly 12 billion pounds, or about $15 billion at current exchange rates, from an arm of Qatar’s sovereign wealth fund and other investors. Such deals allowed the bank to avoid a bailout. The fraud office has been scrutinizing whether the bank properly disclosed an agreement with Qatar that involved a payment for advisory services. It was also examining a $3 billion loan that Barclays made available to the Qatar government.

The bank said it was “considering its position” in relation to the accusations. A lawyer for Mr. Jenkins said his client would “vigorously defend against these charges.”