The chairman of Barclays Bank is set to step down after it was fined for attempting to manipulate the inter-bank lending rate, the BBC reported on Sunday. Marcus Agius will announce on Monday that he is to leave his post in the face of public and political fury over the bank\'s efforts to distort the rate at which banks lend to each other, according to the BBC. Business Secretary Vince Cable earlier backed calls for a criminal investigation into bankers involved in the scandal, which cost the bank £290 million ($450 million) in fines. Traders at the bank are suspected of manipulating the Libor rates, which play a major role in international financial markets and affect businesses and consumers, in order to skew the markets in their favour. It emerged earlier Sunday that The Royal Bank of Scotland had sacked four traders over their alleged involvement in the affair, raising suspicions that the practise was widespread. Prime Minister David Cameron on Friday reiterated his intention to bring Barclays chief executive Bob Diamond and others at the bank to account. \"I think he and frankly the whole management team have got some very serious questions to answer,\" the British premier said. \"How many people were engaged in this activity, who were they, who was managing them, to whom were they accountable, how much did the management of this company know about what was happening?\" The bank\'s actions distorted one of the main indicators of its financial health. Diamond was in charge of Barclays\' investment arm at the time. The scandal is a fresh blow to Britain\'s embattled banking sector following massive bailouts paid for by taxpayers. Cameron also vowed not to let possible fines end up being used by the bank to reduce its annual tax bill. \"These fines should not be reducing the bills of banks they should be reducing the bills of hard-pressed taxpayers and that is how it is going to be,\" he said.