Investec has maintained its buy recommendation on British Polythene Industries (BPI) after the manufacturing firm revealed this morning that full-year results would come in at the top end of expectations.The broker notes that trading has remained consistent with that described in the group's November trading update. "The group has benefited from structural changes effected in the UK in recent years and a strong European performance," said analyst John Lawson.Investec predicts that BPI can generate around £18.5m in full-year pre-tax profits, a 17% rise on last year's £15.8m.A 400p target price is kept.Shares were trading 1.09% higher at 323.5p by 12:20 on Tuesday.BC