A Goldman Sachs executive director has resigned from the bank, declaring that he was more proud of his involvement in the "Jewish Olympics" in Israel than any of his work at the company.

Greg Smith, who has spent 12 years at the firm in the US and London, explained his decision in a devastating piece in the New York Times. He said the current environment was "as toxic and destructive as I have ever seen it" and said he felt ill when he heard "how callously people talk about ripping their clients off".

Although he said he had no evidence of illegal behaviour, he said that what was best for the client was being sidelined and that he could not longer "in good conscience say that I identify with what it stands for".

Mr Smith said that the workplace culture – which was about more than making money - was once an integral part of Goldman Sachs's success

"The culture was the secret sauce that made this place great and allowed us to earn our clients' trust for 143 years," he said. "I look around today and see virtually no trace of the culture that made me love working for this firm for many years.

"I truly believe that this decline in the firm's moral fibre represents the single most serious threat to its long-run survival," he added. "It astounds me how little senior management gets a basic truth: If clients don't trust you they will eventually stop doing business with you. It doesn't matter how smart you are."

The South-African born Mr Smith, twice represented South Africa twice at the World Maccabiah Games in Israel, which he referred to as the "Jewish Olympics". He said: "My proudest moments in life - getting a full scholarship to Stanford University, being selected as a Rhodes Scholar national finalist, winning a bronze medal for table tennis at the Maccabiah Games in Israel - have all come through hard work.

"Goldman Sachs today has become too much about shortcuts and not enough about achievement. It just doesn't feel right to me anymore."