The answer is no. The governments bonds are money borrowed from the State and as such are secure. So you have the security that you will have back your money and its interest (normally) the day in which they are matured. The word "normally" is connected with situations which are extraordinary and have great impact in the life of one country (for example an war). In that cases the bonds cannot be given but not denied. Never. Even in its more difficult days normally every government give the money of bonds and their interests to the owners. Not only that but offer others (if it is in difficulty) will higher interest. Even, the main thing that the people invest in bond is not the interest but the security of the money given to buy the bonds. Is the given of the money to the State which never deny its debt to its owners. For more about government bonds you can learn here: https://en.wikipedia.org/wiki/Government_bond