"The main driver underpinning Moody's decision to downgrade the UK's government bond rating to AA1 is the increasing clarity that, despite considerable structural economic strengths, the UK's economic growth will remain sluggish over the next few years due to the anticipated slow growth of the global economy and the drag on the UK economy, " Moody's said.

BBC: UK loses top AAA credit rating for first time since 1978

The risk must be that whatever government emerges will only prove an interlude before a fresh crisis, in which external pressure once again is required to force Rome to confront the Italian economy's structural shortcomings, perhaps in return for a deal with the European Central Bank to support the government bond market under its Outright Market Transactions program.

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Although current and prospective central bank purchases of debt, especially in Europe, should continue to support bond prices, economic growth continues to be held back by significant fiscal tightening, associated business uncertainty and structural changes there.

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