LONDON (Reuters) – The downturn in euro zone business activity surprisingly deepened in December, according to a closely watched survey which indicated the bloc’s economy is almost certainly in recession. Last quarter the euro zone economy contracted 0.1%, official data has shown, and December’s Purchasing Managers’ Index (PMI) – seen as a good gauge of economic health – suggested activity has now declined in every month of this quarter. HCOB’s preliminary Composite PMI, compiled by S&P Global, fell to 47.0 this month from November’s 47.6, confounding expectations in a Reuters poll for an upti…