The U.K.’s largest retail banks and lenders have paid about $75 billion for misconduct — including judgments, settlements and related legal costs — over the past 15 years, a new study released Monday showed. "Persistent misbehavior” by British banks had cost them about 1 pound ($1.41) in every 4 pounds ($5.66) of pretax profits earned, the study said.

Despite being hit by a range of scandals such as manipulation of foreign exchange and benchmark interest rates and mis-selling payment protection insurance, these banks have continued to pay billions of pounds in bonuses to executives, the study by the independent think-tank New City Agenda said.

"The profitability of U.K. retail banks has been imperiled by persistent misconduct," said John McFall, a director of New City Agenda and former Chairman of U.K.’s Treasury Committee.

"This has made every citizen poorer through our pension funds and our ownership of the bailed out banks," he added.

The report found that between 2000 and November 2014, U.K. retail banks had set aside over 38.5 billion pounds ($54.44 billion) to pay compensation to customers. However, the penalties and compensations paid over the Payment Protection Insurance scandal pushed the misconduct bill to almost 53 billion pounds ($74.94 billion) — the biggest single conduct issue for U.K. banks.

The scale of the payouts has hampered banks' efforts to rebuild capital, restricted the amount they are able to lend and reduced dividends for investors, the report said.

Earlier in March, the U.K.’s banking regulators toughened their stance towards fiscal mismanagement of banks' assets by senior employees by passing a law that holds senior managers responsible for any wrong doing on their watch. The reform also made reckless management of a bank leading to its failure, a criminal offence.