Royal & SunAlliance (R&SA) has attempted to play down the loss of Brendan McManus, managing director of its broker division, who resigned this week.
The departure of McManus, who is to become chief executive of Willis UK & Ireland, will be a blow to the insurer.
One senior broking source said: "They have been hit for six. McManus will be hard to replace."
The company said that a strong management team was in place, but conceded that there was no immediate strategy for dealing with the transition.
A spokesman said that UK chief executive Bridget McIntyre would be taking on a "more active role", but it was "too early to say" if that would involve broker-facing responsibilities.
McManus' departure came as no surprise however. There had been rumours for some time that he was waiting for an appropriate opportunity to leave.
Speaking to Insurance Times, McManus said: "I love the company and the people in it, but I did want to do something different, more in distribution."
McManus played down the impact of his resignation saying that he had a "very strong and experienced" management team.
"I am not the only one dealing with brokers."
The R&SA spokesman said there were "a number of strong internal candidates," but stressed that no appointment was imminent.
McManus, who has been with R&SA for over 20 years, will leave the company on 31 July.