Service sector activity grew last month at its slowest pace since April 2009, with a marked fall in hiring as employers worried about an economic slowdown and public spending cuts, a survey showed. The headline Markit/CIPS services purchasing managers' index dropped to 51.3 in August from July's 53.1, a much sharper fall than the decline to 52.9 forecast in a Reuters poll. The downbeat services reading follows bigger-than-expected falls in the PMIs for manufacturers and construction, though all are still above the 50 line that divides growth from contraction. Markit said the three surveys suggested that British GDP growth slowed to 0.5 per cent in the third quarter from a nine-year high of 1.2 per cent the quarter before.