Charles Thomson, chief executive of Equitable Life, has been reprimanded by the Institute and Faculty of Actuaries for misconduct, after being found guilty of bringing the profession into disrepute over his faked job reference.

The decision of the profession's adjudication panel has only just been published, though the hearing took place place on February 22 and did not prompt the customary issuing of a press release on disciplinary matters.

Thomson protested to The Herald last night that the matter had been "completely trivial".

In a further twist, the complaint against Thomson is understood to have been brought by Chris Headdon, his predecessor and the man who hired him while allegedly in full knowledge of the job reference incident.

Headdon was given a public reprimand by the profession in March for his role in Equitable's near collapse.

The profession summoned Thomson to answer the charges after he appeared as Equitable Life's key witness in the ill-fated £3.7bn legal actions it brought against Ernst & Young and 15 former directors, which were abandoned in December 2005 after costing policyholders £45m.

Under merciless cross-examination from Ernst's counsel, Thomson had admitted in court in April 2005 that he himself was the author of the glowing reference to his "exceptional record of success" at Scottish Widows, where he was deputy chief executive from 1995 to 2000.

The reference concluded: "We will miss his intellect, integrity, and energy and feel sure he will bring great value to other organisations at the highest levels."

The adjudication panel said: "There was clear evidence that the respondent had in fact presented a character reference purporting to be from the chief executive of his former employer which he himself had written and which had not in fact been approved by his former employer."

Although Thomson had withdrawn the reference soon afterwards, he had given no indication that it was provisional. "Such conduct on the part of an actuary, particularly a senior member of the profession seeking a senior position, is prima facie a failure to comply with the standards of behaviour and integrity which the public and the profession might reasonably expect of a member. The conduct brought the profession into public disrepute."

It concluded: "However, the panel noted that the respondent was under considerable pressure, his departure from his previous employers having been announced on only the evening previous to the presentation of the character reference.

"The respondent withdrew the reference within a few hours on his own initiative. The respondent accepted that there had been misconduct and accepted a reprimand."

Thomson said last night: "This is all historical stuff. This is all concerned with three hours, six-and-a-half years ago, and it had nothing to do with my appointment to the society."

He said the incident had been "known to the nominations committee and was of no consequence".

He said that as a disciplinary matter it was "completely trivial", and that "it is actually quite hard to prove you are innocent".

Paul Weir, an Equitable action group campaigner, commented: "I note this was published after the society's annual meeting. I would like to know how he (Thomson) has kept his job."

Alastair Dunbar, spokesman for Equitable Life, said: "Mr Thomson was appointed by the society in full possession of the facts and his success at the society since then speaks for itself."