Quantities of cigarettes and other tobacco products released for consumption at: https://www.uktradeinfo.com/index.cfm?task=bulltobacco
Household final consumption expenditure (i.e. total aggregate spending) available from Consumer Trends published quarterly by ONS.
Average weekly household expenditure on tobacco from the Expenditure and Food Survey: last survey done in 2007. http://www.statistics.gov.uk/downloads/theme_social/Family_Spending_2007/FamilySpending2008_web.pdf
Some additional analysis required to derive spend per capita, as opposed to aggregate spend or spend per household.