For individual investors, the bond will offer a safe, longer-term option.

The 50-year bond offers them a long-term match that is hard to find.

"Given their inflation rate of 3 percent, their long bonds offer a better real return, particularly if one factors in foreign exchange costs."

"If rates stay at current levels, the stock market will have difficulty making progress; bonds offer too attractive an alternative to stocks."

For state and local governments, the bonds offer more than immediate cash.

Other serial bonds offered higher yields of up to 6.70 percent in 1997.

The 30-year bond does not even offer a good comparison with interest rates in other countries, where 10-year maturities are typical.

And with bond yields at the high end of their recent range, bonds offer a good value again.

The bond offered 1.25pc over the retail price index for 10 years.

The bonds offer one group of investors an interest rate that is adjusted every 35 days.