Churchill is celebrating topping the one million mark: for the first time in its 11-year history the direct writer has over one million car policyholders.
Churchill added 350,000 new policyholders to its books last year, and boasts a renewal rate of about 90%.
It currently holds a 5% market share.
Actuaries Bacon & Woodrow gives Churchill an operating ratio in 1998 of 105.2% compared with the market as a whole of 124.0%.
The increase in sales led to a second call centre being opened up at Teesside last year.
Churchill is part of the Winterthur Group, ranked in the top ten financial services group.
The company also underwrites home, pet and travel policies.