Provided an endowment runs for at least 10 years, it is regarded by the taxman as a "qualifying policy" policy. What this means is, an endowment that runs for at least 10 years and qualifies for a tax-free payout at the end of the term. However…
Endowments, qualifying or not, are not tax-free. The proceeds of an endowment are free of all taxes. The proceeds are, however the growth of the policy has been taxed throughout its life. Therefore it's more accurate to say that the proceeds of endowments are free of any further tax liability on your part. The tax man has already charged. The life assurance company pays tax on the investment growth in two ways. First of all it pays tax at 22% on the capital gain of the assets of the fund, in other words the growth in value of the shares etc. Secondly it pays 20% tax on income, this would come from the share dividends etc.
The actual tax paid is less however, because the insurance companies are allowed to offset certain expenses against the tax bill, in effect reducing it. For lower rate tax payers any tax paid within the fund is not refundable, this means that lower rate payers would end up paying tax they wouldn't have normally been liable to. Standard rate payers simply would be paying the equivalent tax they would of paid on alternative investments.