Annuity rates may change from time to time and are only guaranteed for a limited time period. If the annuity income does not match the guarantee you will not, for that reason alone, be entitled to compensation under the Financial Services Compensation Scheme.
An annuity is a long term investment as it cannot be cancelled or transferred to another provider once set up. It does not have a cash-in value. Annuities may have cancellation rights but these are only available for a limited period.