LONDON (Reuters) – Britain’s manufacturing sector suffered a setback in its attempts to return to growth as output and employment fell more sharply in December than the previous month, according to a survey published on Tuesday. The final reading of the S&P Global/CIPS manufacturing Purchasing Managers’ Index (PMI) weakened to 46.2 in December, ending a run of three months of improvement and down from a seven-month high of 47.2 in November. The reading was also down slightly from a preliminary December estimate of 46.4 and was below the 50.0 growth threshold for a 17th month in a row. Britain’…