Markit's and the Chartered Institute of Purchasing & Supply's services purchasing managers' index (PMI) for the U.K. rose to 54.9 in October from 53.3 in September, exceeding expectations for a rise to 54.5.
A reading above 50 indicates expansion in the sector.
The increase was driven by a faster growth in business activity and stronger job creation.
"The survey data point to GDP rising at a quarterly rate of 0.6% at the start of the fourth quarter, up from 0.5% in the third quarter. Such an improvement, together with the revival in hiring signalled by the three surveys, with job creation hitting an eight-month high in October, may coax more policymakers into raising interest rates before the end of the year," the Chief Economist at Markit Chris Williamson said.