Royal & SunAlliance (R&SA) and Primary General Insurance have ended binding authority deal two years early.
The deal, between R&SA, Primary GI and its sister company Rural Insurance Group, was expected to span three years.
In a statement Primary said the decision was "mutual and amicable".
Norwich Union will take over the deal, which it has expanded for a further five years.
R&SA will remain on-cover for existing business and an "appropriate run-off" will take place, said both companies.
