The great popularity of Denby made jugs invited imitation and both Langley Mill (click button for images) and Salopian Art Pottery (click button for images) made jugs that would be almost indistinguishable from Denby if they hadn't been signed. Denby jugs are known marked J. Pearson. It had been assumed this was James Pearson of Brampton, but I have seen one clearly marked “J. Pearson / Blackpool” so they were made by Denby for a Blackpool retailer (click button for image) 1.
A recent find has been a Denby style jug marked Brownlow Gorton, presumably from Slack & Brownlow's Abbey Hey Pottery at Gorton, Manchester (click buttonfor image).
A distinguishing feature of Langley Mill jugs (marked Lovatts of Langley Mill) is a shoulder line of dots which Denby did not use and Doulton sprigs for the hunting scene on the lower section.
I have also seen unsigned jugs with sprigs seemingly identical to Denby but showing a Doulton type stag hunt rather than the fox hunt that is the Denby standard. Whereas Denby and most of the other look-alikes have a flat base these have a 4mm raised rim. They can also be attributed to Lovatt, as I have now seen 1 pint and 2 Quart (4 pint) examples impressed "Langley Ware" in a style of mark dated to the period 1883 - 1890 2.
1 James Pearson, China Dealer at various Blackpool addresses 1876 - 1901 Listed before as William Pearson and after as James Pearson & Sons.
2 Langley Mill Pottery, John & Jenifer Giblin , 2002