A still more pertinent question is: who owns the company?
If it is owned by another large insurance company, a major clearing bank or one of the large merchant banks, then clearly the resources available to it are far greater than if it is owned by family interests.
If it is owned by some intermediate organisation, say a minor financial company or group that is not part of the financial establishment, then this may also indicate a slimmer availability of resources to back it up.
In general, therefore, it is sensible to stick to companies that are sound in their own right, or are owned by a substantial and dependable parent company.
It is clearly in your interests to choose a sound insurance company with which to take out a policy, and it is therefore desirable to have some criterion for selection. Unfortunately, this is not an easy matter. While one can certainly say that the large old-established life insurance companies in the UK are generally sound, one equally cannot say that all small or recently formed companies are unsound. It is often the small and enterprising new company that introduces a new and attractive policy which is not available from its larger competitors. The "young" company has every incentive to be competitive... see: Sound or Unsound?