Firms that are consistently below par include insurers Norwich Union and Prudential, while those with a far better record include Standard Life and Skandia.

The research, by financial data scrutineer Citywire, is based on the views of more than 360 financial planners who were asked to score companies according to the service they provide in six key product areas.

In protection insurance, for example, Skandia and Friends Provident were judged the best, while Norwich Union, Scottish Provident and Prudential were the worst.

Citywire's David Turner, who devised the service ratings, says: 'Though the analysis focuses on the quality of service received by financial advisers, poor service can impact badly on the consumer.'

Prudential said it was continually striving to improve service. Norwich Union said improving service was a 'key goal' for 2008.