The man at the centre of the biggest fraud probe in US corporate history yesterday spoke at a meeting of compliance specialists in Bermuda.

Andrew Fastow, the former chief financial officer at energy firm Enron, which collapsed in 2001, told Bermuda’s company watchdogs that problems start when finding legal loopholes becomes more important than principled business practice.

Mr Fastow, who spent six years in jail after pleading guilty to securities fraud charges in 2004, said: “The Enron deals were not secret — they were all approved by accountants, attorneys and the board of directors.”

He added: “I may have been technically following the rules, but that wasn’t the point — I undermined the purpose of the rules.”

And he added that the deals also appeared in the firm’s financial statements.

Mr Fastow was speaking at the Y Compliance financial crime and compliance seminar, held yesterday at the Fairmont Southampton — run on the theme of “who can you trust?”

He told the audience: “I’m not going to make any excuses for what I did, rewrite history or minimise what I did.”

Mr Fastow said he was now a popular speaker at conferences since he was released from jail in 2011.

He added: “That’s a tough thing to live with — I’m glad I get to do this sometimes, but it’s tough. I’m here because I went to jail and because I was guilty.”

Mr Fastow was the CFO at Enron — which became the seventh biggest firm in the US before its crash — from 1988 until it folded.

Since his release from prison, Mr Fastow, who gained an MBA in Finance after a first degree in Economics and Chinese, has worked in litigation support at a legal firm in Houston, Texas.

He also acts as a consultant to directors and managers of companies on how to spot potentially serious finance, accounting, compensation and cultural problems in firms. Mr Fastow said: “It never dawned on me I was committing fraud. It clearly was fraud and it’s easy to see that retrospectively.”

He explained that CFOs “make these decisions in an environment where the rules are very complex, very ambiguous and sometimes non-existent.

“We saw that as an opportunity to use the ambiguity to our advantage, to use the ambiguity. It’s figuring out a way to get around the rules, get around the law. This is what we did at Enron — to an excessive degree.”

He said that Enron used off balance sheet transactions to cut the apparent debt of the firm and make it appear it was performing better than it was.

Mr Fastow added: “Culture matters a lot — I’d like to think that if the culture would have been different I would have acted differently — but I don’t know. I contributed to making the culture worse.”

And he said: “I don’t think you can regulate the problem away because there is an entire industry of people out there, very clever people, who do nothing but look at ways to manipulate rules to their advantage.”

McKeisha Smith, one of the organisers of the conference, said: “It’s been very positively received — the information was very down to earth. All jurisdictions think alike as to the way compliance is evolving. It’s all about keeping up with standards and best international practices.”

She added: “Mr Fastow was one of the highlights. The main thing is the evolution of compliance and keeping organisations heading in the right direction within the laws out there. “Mr Fastow’s main message was that you can’t undermine the principles of the law.”