ACCC chairman Graeme Samuel has once again lashed out at critics of the Commission's recent bank merger decisions and admitted to "grinding his teeth" at "populist" commentary.He also admitted that the Australian Competition and Consumer Commission did not know how the financial system should evolve, but said it would continue to try to forecast whether there was likely to be substantial lessening of competition in financial markets.The ACCC would be "very cautious" over any future bank merger proposals, he said.He told a panel discussion organised by the Australian Centre for Financial Studies in Melbourne that the ACCC had conducted "a fairly rigorous analysis of what's been going on in the sector"."And it is, I have to say, [a matter]of intense frustration when we see so-called competition experts, particularly those in academia, who are out there making fairly glib populist comments about what is happening in the sector and what the problems are."Because that can tend to mislead the community and sometimes [lead] those who are in charge of setting our laws and setting our regulations into erroneous directions based on erroneous assumptions and commentary about exactly what's occurred."Samuel did not name the academic critics he has in his sights. But they are likely to include University of NSW associate professor and long-time ACCC critic Frank Zumbo.Samuel once again defended the ACCC's approval of Westpac's St George takeover and the CBA's takeover of BankWest, saying BankWest was in danger of having A$16 billion in funding removed by troubled UK parent HBOS in late 2008.He found it "bemusing… that a couple of so-called competition experts in academia subsequently were out there saying, 'Y'know, those two mergers have spelt the death of competition in the banking and finance market for the next 50 years'.""Well, forgive me, but they are not Nostradamus, number one. [And] they had done no analysis of what was occurring in the banking and finance market at all, but this happened to suit the particular news grabs in the media concerned."