The region would fall into a debt-deflationary spiral, gross domestic product would fall by a cumulative 5pc. The debt restructuring could wipe €800bn (£686bn) from private sector wealth in the eurozone.
The knock-on effect would be a second recession in the UK, with a 1pc fall in GDP in 2012 followed by a 0.2pc fall in 2013.
That is just one of four possible scenarios examined by PwC in a report entitled What next for the eurozone?
The accountancy firm goes further than Bank of England policymakers and Office for Budget Responsibility forecasters who in the past month have shied away from quantifying the impact of the various possible outcomes of the eurozone debt crisis.
However, PwC falls short of measuring the possible impact of a total disintegration of the monetary union, concluding this to be unlikely.