Bonds carrying a UK government guarantee of both their principal and interest. They may be for fixed sums of money, or index-linked to the retail price index. National Savings and Investments is a UK institution providing safe securities for individuals to hold. These are widely held: they provide a return which is completely safe, but on average somewhat lower than that on other investments. The amount of National Savings bonds any individual can hold is restricted.

http://www.nsandi.com/ The website for National Savings and Investments.