Robinson, which manufactures plastic and paperboard packaging, reported a rise in annual profit as plastic resin prices grew.Group revenues increased by 10% to £23.3m in the year ended December 31st 2013. Plastic resin prices were higher by an average of 6% which were largely passed to customers, resulting in higher reported revenues. Pre-tax profit came to £3.7m (2012: £2.8m) after an exceptional gain of £1.1m was made on the sale of the Portland factory in Chesterfield to Sonoco.Rental income was reduced by £0.2m following the sale of Portland so operating profit before exceptional items fell slightly to £2.3m from £2.4m in 2012.Chairman, Richard Clothier said: "The sale of the Portland factory in Chesterfield to Sonoco results in reduced rental income but leaves the group with cash to fund the growth by acquisition which we have announced since the year end. Growth in revenues is continuing in 2014 to date."The total dividend was raised by 12.5% to 4.5p.Shares fell 2.41% to 202.50p at 14:39 on Thursday.RD