LONDON (Reuters) -Sterling drifted lower against the dollar on Thursday as data showing resilient British business activity in March failed to prop up the currency for which traders are now anticipating a slower pace of monetary tightening by the Bank of England. By contrast, buoyant U.S. job data fuelled speculation the Federal Reserve would raise interest rates by half a percentage point at its next policy meeting in May, giving the greenback a boost. At 1600 GMT, sterling was 0.16% lower against the dollar at $1.3186 and 0.22% down versus the euro at 83.47 pence after hitting a two-week hig…