O&M was behind the £20m controversial launch campaign that included fly posters of a lost dog, Lucky, pasted on trees, buses and lamp-posts in the London area. It was seen as a brave attack on the insurance market as it focused on brand in a price-driven sector.
The Advertising Standards Authority (ASA) upheld 15 complaints that the fly poster campaign could undermine genuine attempts to find lost pets.
CCHM, a specialist financial agency, is an existing More Th>n roster agency and was appointed at the launch of the brand to handle the marketing of investments.
The split with O&M follows poor results for More Th>n's parent Royal & SunAlliance. Last week, chief executive Bob Mendelson said R&SA's results were disappointing, but were affected by the unavoidable costs of the attack on the World Trade Center as well as an increase in asbestos-related claims. RSA's operating profit plunged from £462m for 2000 to £16m in 2001.
Mike Tildesley, marketing director at More Th>n, was unavailable for comment, but a spokesman for the brand denied that poor results contributed to the split with its ad agency.