Robinson shares soared over 16% after the packaging manufacturer revealed a 78% profit increase in 2010 on sales that grew 13%.Pre-tax profit for the 12 months to 31 December surged to £1.71m, from £0.96m in 2009, as a better customer mix and lower labour and electricity costs resulted in a gross margin improvement from 19% to 20%. Operating costs were also broadly flat at £3.69m, compared to £3.61m previously.Revenue increased from £21.95m to £24.83m, but excludes the group's loss-making US paperboard business which was closed in December, driven largely by the relative strength of the Canadian dollar and weak US demand."We remain conscious of the possible effects of economic trends and government policy on our costs and consumer demand, but due to the group's exposure to the usually resilient food, drink and toiletry sectors we do not expect revenues to be greatly affected. Our progress so far in 2011 is in line with the board's expectations," said chairman Richard Clothier.The final dividend was flat at 1.75p. Basic earnings per share from continuing operations grew to 7.8p, from 4.6p in 2009.BC