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"What's the origin of this crisis? It's frankly that banks started buying and selling products that they didn't understand," Mr Darling said.
"It's hardly surprising then that there's this almighty car crash. The tragedy is that it wasn't them [the bankers] that suffered, it was everybody else because the world economy plunged into a recession."
The chancellor has also unveiled a new policy that he wants to introduce at the meeting in Pittsburgh with a view to having it agreed at the G20 finance ministers' summit in November.
At the summit in London, it was agreed there would be a blacklist of countries that were operating as tax havens.
Mr Darling's idea is to also have a blacklist of countries that are regulatory havens where the rules and regulations companies have to follow are less onerous.
"People can set up in the Caribbean or South America, the regulators here can't get the sort of information they want and that sort of secrecy leads to instability," he said.
"I think we can get an agreement this weekend to outlaw that sort of activity."
The rules he wants to introduce would allow sanctions to be taken against countries that do not have strong enough regulatory regimes.
The other part of the plan would be that there could be sanctions taken against UK-based companies that did business in blacklisted countries.
So, for example, if a British bank invested in an investment fund based in a blacklisted country, the regulator could penalise it by saying it had to keep more of its cash in reserve.
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