Lloyd Hanks, managing director of Greatminster Group's General Network (TGN), has resigned after only six months.
The resignation coincided with the company admitting that, with an uncertain regulatory climate and tough market conditions, it is struggling to carry out plans to enhance its membership base.
Hanks said: "Having successfully implemented the programme of change, I came to the conclusion that now is not the right time to move TGN to the next stage. I therefore offered my resignation. I am in no doubt, however, that TGN will continue on its road to success."
A statement from the company said: "Mergers, market consolidation and the impact of changes in the personal insurances sector, together with the uncertainty over future regulation are all having a negative effect on TGN's ambitious plans."
David Milne, group managing director at Greatminster, said: "We would like to place on record our appreciation and thanks for the work he has done over the past six months and wish him every success for the future."