The widening to base mug is similar in shape to mugs commemorating George Holyoake and Co-operative Society establishments at Sunderland and Ryhope (Silksworth branch). http://www.unitedcollections.net/co-operative-society.html The straight sided, smaller mug seems to be less common. Apart from the added colour the base advertises "J. WHITTAKER FRUIT PRESERVER SUNDERLAND"