Angela Merkel’s staunch defence of the single currency, made in the Bundestag this month, is widely shared by other European leaders. The German chancellor’s sentiment demonstrates the political will not to let Europe’s sovereign debt crisis undermine the single currency.

So long as this level of political capital is invested in the euro, monetary union is highly likely to survive. However, the talk among investors and some European politicians this week has been of Greek default. The graphic below outlines the likely consequences of a default by Greece. It is a description, not a prediction – a description that includes the possibility of the break-up of the eurozone, though even in the event of Greek default that outcome is far from inevitable.

Plan A, as far as European authorities are concerned, is to implement the agreement struck on July 21. Under the deal, Greece was offered a second programme of loans, worth €109bn, including the guarantee that Athens would not need to return to financial markets for years, borrowing instead from other European countries and the International Monetary Fund at low interest rates. The private sector would take a writedown of its debt to help ease the burden facing Greece. And the European financial stability facility – the temporary bail-out fund – would become more flexible in order to limit contagion from one eurozone country’s bonds to others.