The former chief executive of Enron, Mr Jeffrey Skilling, yesterday blamed its collapse on "a classic run on the bank" against a company which was sound, solvent and highly profitable.

Speaking to a Congressional hearing, Mr Skilling claimed that he had no knowledge of "any attempts to conceal liabilities or inflate profits". He said that, as chief executive, he had to rely on information relayed to him by subordinates and could not know all of what went on in the company.

Mr Skilling, widely seen as a "control freak" and one of the villains of the piece, insisted that when he resigned from the company last August he had no awareness of the financial precariousness of the company.

He said he had been immensely proud of the role of the company in transforming the energy markets but in retrospect things "look different".

"I am devastated by and apologetic for what Enron came to represent."

Five senior former Enron executives - including its former chief financial officer, Mr Andrew Fastow, pleading the Fifth Amendment - yesterday refused to testify in Congress on their role in the company's collapse. The House Energy and Commerce Committee was hearing evidence from a series of what one member called the "architects of Enron's house of cards" and another, "economic terrorists".

One who did testify, however, was a deeply nervous Mr Jordan Mintz, the senior in-house lawyer, who started warning in numerous unheeded memos a year before the collapse of conflicts of interest and dubious transactions.

Mr Mintz had repeatedly but unsuccessfully attempted to get Mr Skilling to formally sign off his approval of multiple partnership agreements.