Besides what stygiansonic said: The article does not claim that UK bonds have been paying 2.5~4% since 1720. That range refers to the current nominal rate for

Besides what stygiansonic said: The article does not claim that UK bonds have been paying 2.5~4% since 1720. That range refers to the current nominal rate for those bonds. Those bonds have been restructured/refinanced several times along the years. That is, the UK "soft-defaulted" a few times. Sovereign bonds aren't risk-free, especially not in the very long term.