London--Jan. 15--Producer output and input prices for the U.K. came in weaker than expected in December, with input prices driven down largely by the fall in crude oil prices and output prices hit by the consequent decline in the price of petrol. Unadjusted output prices fell 0.1% on the month, and rose 2.4% on the year, compared with forecasts of a 0.1% monthlyrise and a 2.7% annual increase. Seasonally adjusted input prices fell 3.5% onthe month and rose 5.7% on the year, below analysts' expectations of a 2%monthly drop and a 7.6% annual increase.