Half yearly profit powered ahead at gaming model specialist Games Workshop after it benefited from a weaker pound, cut costs and saw an increase in royalties.Pre-tax profit surged to £7.9m for the six months to 29 November 2009 from £3.0m the same time a year earlier. Revenue rose to £62.5m from £61.2m before. At constant currency revenue fell to £58.5m from £61.2m in 2008. Gross margin rose to 74.4% from 71.4% in 2008.The maker of Warhammer said royalties receivable more than doubled to £1.2m in the six-month period from £0.5m previously. Gross margin increased as it sourced cheaper raw materials, cutting staff and renting stores with lower rent. Commenting on the results, chief executive Mark Wells said, "With improved operating margins we continue to open Hobby centres, confident that we can grow Games Workshop profitably in all existing territories.""Games Workshop's core fundamentals remain strong. Our gross margins are improving, our costs are under control, our return on capital is increasing and our cash flow is good. The board remains confident in the future growth and profitability."