Conservative leader David Cameron has called for tougher action against those suspected of financial wrongdoing so they can be "held to account".
"There should be a day of reckoning. A day when we would not flinch from spelling out the rightful consequences of irresponsible behaviour," he said.
There should not be "one law for the rich" and another for everyone else.
He also accused ministers of making the recession "longer and deeper" by failing to guarantee loans to business.
He urged ministers to "take action now" by underwriting lending to firms, as bank recapitalisation schemes were "failing" to ensure this.
The Tory leader, addressing the Thomson Reuters information firm in London, said the financial services industry had had its name "blackened" and that more needed to be done to investigate and punish fraud.
'No stone unturned'
In the US, hedge fund boss Bernard Madoff has been charged with fraud worth £33bn.
The Royal Bank of Scotland said it could potentially lose about £400m if all its investments with him had to be written off.
In the home of capitalism, a sense of fair play is dramatically in evidence. Why aren't we doing the same in Britain?
Spain's largest bank, Santander, which owns the UK High Street banks Abbey, Alliance & Leicester and Bradford & Bingley, said one of its funds had £2.7bn invested in the firm run by Mr Madoff.
Mr Cameron praised efforts the efforts of the US authorities, who had made sure no "stone is being left unturned", particularly in investigating the mortgage industry.
He said: "In the home of capitalism, a sense of fair play is dramatically in evidence. Why aren't we doing the same in Britain?
"Doctors who behave irresponsibly get struck off. Bankers who behave irresponsibly should face professional consequences. And, for sure, if anyone is found to have behaved criminally they must be prosecuted.
"Are the government seriously saying that nothing untoward could have happened over here? How can anyone believe that in the worst financial crisis of our lifetime no proper and thorough investigation needs to happen?"
He added: "If we're going to build a strong and fair society, individuals must carry the consequences of their own actions - regardless of who they are, where they come from, and what their background is."
In his second major speech on the economy in a week, Mr Cameron also repeated his attack on the government's handling of the crisis and its failure to underwrite lending to firms.
He said: "Because the recapitalisation is failing, we've proposed a National Loan Guarantee Scheme to underwrite loans to businesses.
"The government could and should take that action now, today. Every day it delays, the government is making the recession longer and deeper."
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