I raised this key point in the House of Commons recently in a written question:
To ask the Chancellor of the Exchequer how many of the lowest paid no longer pay income tax as a result of changes to taxation introduced since May 2010 in (a) the UK, (b) the North East
Hansard source (Citation: HC Deb, 4 December 2013, c671W)
David Gauke (The Exchequer Secretary):
The cumulative effect of the Government's increases in the personal allowance for those aged under 65 years (born after 5 April 1948 from 2013-14 tax year) since 2010-11 will take 2.7 million people out of the income tax system by April 2014. 110,000 of them are in the north-east region.
These estimates are based on the 2010-11 Survey of Personal Incomes, projected to 2014-15 using economic assumptions consistent with the Office for Budget Responsibility's March 2013 economic and fiscal outlook.