Revenues were down at WH Smith in the half year to February 28, but efficiency measures helped the newsagent chain post a rise in pre-tax profits.Revenues slipped to £716m from £731m over the same period the previous year, while pre-tax profits edged up to £62m from £61m.At the travel business, which mainly consists of the company's stores in airports and railway stations, total sales grew by 2% though they were down by 2% on a like-for-like basis, partly due to the decline in air travel. Margins were lifted by better use of space and more sales of higher margin products such as books, WH Smith said.The company's 569 High Street stores saw sales fall by 4% both on an absolute and like-for-like basis. The division delivered £5m in cost savings through measures such as improved use of technology and further supply chain efficiencies, the company said.WH Smith paid an interim dividend of 6.1p a share, up by 13% from the same period last year.'Looking forward, we remain cautious about consumer spending and our plans reflect this. We are confident in the outcome for the full year,' said chief executive Kate Swann.