Standard Life policyholders have voted in favour of a rule change aimed at making it more difficult to float the company on the stock market.

Under the rule change, Standard Life members wishing to force a vote on taking the company public would have to garner support from 1,000 other policyholders, up from just 50 previously.

Ninety-three percent of the 195,000 policyholders who took part in the ballot on Tuesday voted in favour of raising the threshold.

The size of the majority in favour underlines Standard Life members' determination to shore up the company's status as a mutual insurer - one that is controlled by its policyholders.

Narrow escape

Eighteen months ago, Standard Life narrowly avoided being taken public - or "demutualised" - when policyholder Fred Woollard acquired the 50 signatures needed to force a vote on the issue.

Standard Life bosses spent �10m on a campaign urging members to vote against demutualisation.

The new rules voted in on Tuesday are designed to make it more difficult to launch similar wildcat demutualisation bids in future.

Demutualisation debate

Supporters of demutualisation argue that the company's performance would be more dynamic if were run with the aim of maximising value for shareholders.

They also point out that floating shares in the company on the stock market would generate hefty bonuses for policyholders.

But critics say that the company faces a more secure long-term future under the current system, where profits are shared out between policyholders.

Standard Life, which traces its origins back nearly 200 years, is Europe's largest mutual insurer with about 2.3 million policyholders.