The new tax year starts on 6 April 2012 and the basic personal allowance for an individual aged 64 and under is £8,105 providing that annual earnings are £100,000 or less. The personal allowance is translated to a tax code by dividing by 10 followed by a letter and so a person entitled to the basic personal allowance will have a tax code of 810L.
At the beginning of a tax year, HMRC instruct employers to automatically uplift their employee’s tax codes if they have a suffix of L if a tax code has not been issued by HMRC for the new tax year. For example the standard tax code of 747L for 2011-12 will increase by 63 to become 810L for the tax year 2012-13.
For the tax year 2012-13 the emergency tax code is 810L.