The purchasing managers index for the U.K.'s manufacturing sector rose to 55.4 in February from 53.2 in January, market sources said Thursday. That indicates that activity in the sector grew at a significantly more rapid pace than had been expected. Economists surveyed by Dow Jones Newswires last week had forecast the PMI would be unchanged. The January figure was revised up from 52.8. A reading above 50.0 indicates the sector is expanding, while a reading below 50.0 indicates it is contracting. The PMI confirms evidence from another survey of the sector conducted by the Confederation of British Industry, which also recorded a strong increase in activity during February. The index suggests that manufacturing activity is expanding at its most rapid pace since July 2004, despite the pound's recent strength. That makes another rise in interest rates more likely, and should cement market expectations that the bank of England's Monetary Policy Committee will raise rates to 5.50% in the first half of the year.