There has been some surprise expressed that someone from the Office of Budget Responsibility confessed that monetary unions usually fail. The correct statement is monetary unions usually fail, unless they help drive the creation of a new or united country. The US monetary union and the German monetary union were part of the federal constructions in those two emerging countries in the nineteenth century. The Latin Monetary Union and the Scandinavian monetary unions failed, because those countries did not complete or maintain political union.
The Latin currency union was created in 1865 by France, Belgium, Italy and Switzerland. Other countries joined later. The absence of a Central Bank and central monetary authority, the decision of the Papal See to issue devalued silver coins, the gap between silver and gold prices, and finally states’ borrowing needs for the First World War broke the Union, which was effectively ended by the War and given the last rites in 1927.
The Scandinavian currency union of Sweden, Denmark and Norway lasted from 1875 to 1914, with common banknotes from 1901. The termination of Sweden and Norway’s politcal union in 1905, followed by the demands of war finance, killed the monetary union.
Ireland’s monetary union with the UK was ended on 30 March 1979. Ireland enjoyed a freely floating currency against sterling until entry into the Euro in 1999.