Brian Ashford-Russell, the technology stockpicker who picked up a £6m (€9.7m) bonus at Henderson Investors, is having to work harder for his money at his own firm, Polar Capital Partners, as a result of a hitherto unnoticed deal over management fees.

Earlier this year, Ashford-Russell quit Henderson, where he ran the Henderson Technology investment trust, to set up Polar. Shortly afterwards, directors of the Henderson trust moved the fund management contract to him.