Rupert Clarke has stepped down as chief executive of Hermes Fund Managers, the asset manager owned by the £35bn-plus BT pension scheme, after four years at the top.

Following his resignation, Hermes will conduct an external search for a replacement. In the interim, Saker Nusseibeh, current head of investment, will be acting chief executive. Nusseibeh said he had not as yet decided whether to apply for the job.