The Royal Bank of Scotland has dropped its four personal lines insurers in favour of its own subsidiary Direct Line.

It has ditched CGNU, Axa, Zurich and Royal & Sunalliance as underwriters of its personal lines insurance business for its two intermediary subsidiaries.

Natwest Insurance Services (NIS) and Royal Bank Insurance Services (RBIS), in will now use Direct Line, the UK's largest direct writer.

But the four insurers are expected to continue underwriting the commercial lines book of the two intermediaries.

The Royal Bank of Scotland, which acquired the insurance arm of Natwest after its takeover of the bank this year, announced the move this week following a review of the two practices.

As part of a strategic overhaul, which will result in the intermediaries' back offices being integrated, the combined personal lines book will now be underwritten by Direct Line.

NIS and RBIS respectively broke about £150m and £25m worth of premiums before their merger, with about seven million and three million personal lines customers and 850,000 and 200,000 business customers.

The personal and commercial lines books are believed to be equal in strength.

A spokesperson said the move was a natural progression, considering that the Royal Bank of Scotland had the opportunity to capitalise on its ownership of an insurer.

“Direct Line has expertise in personal lines and it would be foolish not to use it,” he said.

“But we are going to continue to broke the commercial book in the traditional way.

“We will also continue to promote our other relates services, such as Mentor, which provides advice on such things as law and tax.”