British manufacturing activity unexpectedly grew at its fastest pace in six months in September because of a rise in new orders, according to a survey of purchasing managers published on Monday.

The Cips/RBS Purchasing Managers’ Index rose to 51.5 last month from 50.3 in August - above the 50 mark which separates expansion from contraction. Although the number indicated only a modest rate of growth, it was the highest since March and well above independent economists’ expectations of stagnation.