Output price index for goods produced by British manufacturers fell slightly by 0.4% in the year-to-date in September, according to figures from the Office for National Statistics (ONS).
It was the biggest annual fall since September 2009, and a bigger decrease than the 0.3% that economists had expected.
Between August and September, factory gate prices declined by 0.9% - although this is unchanged since May.
There was a rise in core factory gate prices, which isn't inclusive of volatile food, beverages, tobacco and petroleum products, however. They increased by 0.9% in the year to August.
The overall price of materials and fuels dropped by 7.4% in the year to September, which Bank of England governor Mark Carney put down to weaker demand.
He told CNBC: "There is persistent disinflation in a couple of major economies," before adding that in the oil market, "there is weaker global demand relative to global potential that is producing a very benign global inflationary environment."