Medical devices and airport scanners maker Smiths Group has reported a healthy increase in half-year profits, up around a quarter.The company grew profit before tax for the six months to 29 January to £188.6m from £148.2m a year ago, and headline profit, which excludes lots of one-off items, by 25% to £224m.Revenue was up by 7%, or 2% on an underlying basis, to £1.37bn from £1.28bn last time. Over a third of the increase was attributed to currency gains on overseas sales. The firm rejected a £2.45bn approach in January for its biggest division, Smiths Medical, where sales fell 2% during the period, but headline operating profit rose 5%. Cost savings and restructuring helped improve margins.A 9% slide in sales and 11% fall in profit at Smiths Detection was blamed on "variable order flow in military and ports & borders".Thecompany's restructuring programme has generated another £6m of savings, taking the total since its implementation in 2008 to £45m. Smiths wants £70m by 2012/13."The business has performed well against a tough but steadily improving economic environment," chief executive Philip Bowman said."Looking ahead, we are enhancing our focus on top-line growth through increased investment in new product development, improved sales and marketing effectiveness, building our footprint in emerging markets, and targeted acquisitions." There's an interim dividend of 11.25p a share, up 7%.