Executives may be tempted to seek as much tax advice as career advice from Sir Nicholas Montagu, the former Inland Revenue boss who has become a mentor and specialist adviser at Iddas, the career counsellor.

In his new role at London-based Iddas, Sir Nicholas will help senior executives move into the public sector. The career civil servant, who was chairman of the Inland Revenue from 1997 to 2004, said the key contrasts between non-executive directorships in the private and public sectors involved the latter having less sovereignty, less corporate responsibility and "absolutely no formal status whatsoever". But, he added: "I think the secret of a successful board is to behave as if the members have the same responsibilities as they would on a plc board, even if they don't."