Note that these allowances are being "modified" (i.e. eventually scrapped):
From 2013-14, the availability of the "age-related" income tax personal allowances will be restricted. The allowance of £10,500 for 2012-13, available to people aged 65 to 74 will be restricted to people born after 5 April 1938 but before 6 April 1948. The allowance of £10,660 for 2012-13, available to people aged 75 and over will be restricted to people born before 6 April 1938.
From 2013-14, the amounts of these allowances will not be increased.