The latest estimates for the number of individual income taxpayers by country and region can be found in table 2.2 “Number of individual income taxpayers by country and region” on HM Revenue and Customs website.
http://www.hmrc.gov.uk/stats/income tax/menu.htm
Information on the number of basic rate taxpayers at constituency level is unavailable. Available estimates for the number of individual income taxpayers by constituency be found in table 3.15 “Income and tax by Parliamentary Constituency” on HM Revenue and Customs website.
http:/www.hmrc.gov.uk/stats/income_distribution/menu-by-year.htm#315.
The information is based on the Survey of Personal Incomes, of which 2004-05 is the latest available, and projected in line with Budget 2007 assumptions.
Sample sizes at constituency level are small and estimates can demonstrate a large variability from year to year, therefore any inference from the information in the table for 2004-05 should take into account the confidence intervals in table 3.15a “Income and tax by Parliamentary Constituency, Confidence Intervals”.