Banks must accept responsibility for past mistakes and show how they can contribute to society and economic growth, the boss of one of Britain's top banks said on Thursday.

Bob Diamond, who took over as chief executive of Barclays at the start of the year, said banks need to re-earn public trust and adopt broader objectives and responsibilities as the industry comes back under fire from an angry public.

We have to build a better understanding of how businesses and banks work together to generate economic growth. Frankly, banks have done a very poor job of explaining how we contribute to society, Diamond said in comments ahead of a BBC business lecture on the subject later on Thursday.

Second, we have to accept responsibility for what has gone wrong, he said.

His comments came as anti-capitalism protests continued in New York, London and dozens of cities around the world, showing that many in society remain angry at the excesses shown by bankers.

Protesters are upset that billions of dollars and pounds in bank bailouts doled out during the financial crisis have allowed banks to resume big payouts to staff, while thousands of people elsewhere lose their jobs as economies skid back towards recession amid the euro zone debt crisis.

In London, the protesters have set up camp outside St Paul's Cathedral in the heart of the financial district, and the row has drawn in politicians, business leaders and even religious groups.

Diamond is one of Europe's best paid bankers, and was criticised in January when he said banks should stop apologising for the mistakes made in the past, telling a panel of lawmakers the period of remorse should end.

UK taxpayers had to step in to bail out banks during the 2008 financial crisis, pumping billions of pounds into Royal Bank of Scotland and Lloyds . Barclays did not take any direct capital, but all banks were aided by extensive funding support provided during the crisis.

(Editing by Helen Massy-Beresford)