UK service sector growth slowed in January, moving closer to stagnation, as new orders decreased for the first time in two-an-a-half years, preliminary data from IHS Markit showed on Tuesday. The CIPS Services Purchasing Managers Index, or PMI, dropped to 50.1 from 51.2 in December. A PMI reading above 50 signals growth in the sector. The latest reading was the lowest for two-and-a-half years and the second-weakest since December 2012, IHS Markit said. The composite PMI, which combines manufacturing, services and construction, fell to 50.3 in January from 51.5 in December.