Encouraged by Wall Street's solid showing overnight, UK shares are set to continue their recent revival, with City traders predicting the top-share index will open at around 5,174, up 45 points from last night's close.Car insurer Admiral announced record half-year figures, with profit before tax 27% ahead of last year at £160.6m, while turnover rose 53% to £1.1bn. The interim dividend has been hiked to a record level of 39.1p.Outsourcer Serco saw headline profit before tax climb 12.2% in the first half of 2011 to £123.6m from £110.2m the year before, on the back of a 4.9% rise in revenue to £2.25bn from £2.14bn. UK and US headwinds continue, the group said, but there are strong future growth opportunities across the group.Advertising giant WPP said billings in the first half of the year were up more than 5% year-on-year at £21.4bn. Headline profit before tax jumped more than 17% to £417m. Newsagent WH Smith said it is trading in line with expectations. --jh