Northern Rock, one of the UK's top 10 building societies, aims to sell up to pounds 65m worth of Guardian's general insurance premiums.
Offices near the society's headquarters will operate as the control centre for the venture, which aims to reach some 190,000 of its 1.4 million members within the first year. The deal follows similar moves with the Woolwich, Halifax and Alliance & Leicester societies.
David Baker, executive director of Northern Rock, said: "Our customers can look forward to the development of a range of modern, competitive products."
Alan Thompson, managing director of Guardian Insurance, said Guardian would continue to underwrite insurance at premium levels at more commercially realistic levels.Reuse content