Heath Lambert has poached a number of senior staff from Aon 's Newcastle office in a bid to bolster its regional presence.
It is understood that at least three directors have defected from Aon, including David Bridges, Derek Foster and Michael Anderson.
Local sources said they had joined rival Heath Lambert. Heath Lambert would not confirm the moves.
Aon said it had received "a number " of resignations, which could "possibly be more than three ".
The departure of the directors would be a blow to Aon 's
operations in the area. It is understood that the Newcastle office handles several of the broker 's major UK clients, including manufacturing and distribution giant Saint-Gobain,with a brokerage thought to be in excess of £1m,and baker Greggs.
An Aon spokesman said it would be contacting clients to "firm up plans moving forward ".
Heath Lambert opened a Newcastle office earlier this month and is planning to open several others around the UK.
Tom Ernoult,managing director of Heath Lambert National, said: "We are making a commitment to becoming a national broker."
Last week Heath Lambert appointed former Marsh director Alan Carnegie as managing director of its Scottish operations.
Ernoult said Carnegie would oversee the opening of a new Heath Lambert office in Glasgow.