John Tiner's appointment as non-executive director at New Star Asset Management will bring the combative former chief executive of the Financial Services Authority on to the same board as a man that threatened to sue the UK market regulator under Tiner's watch for defamation.

Tiner's appointment will place him on the board alongside New Star's founder and chairman John Duffield. The pair clashed in 2004 in the midst of the FSA's long-running investigation into the split-cap investment trust debacle. According to a report at the time, Duffield wrote a letter to Tiner threatening to sue the FSA for defamation after a comment by one of the FSA's press officers that all the firms being investigated by the regulator had "ripped off consumers".