This part of GOV.UK is being rebuilt – find out what beta means

HMRC internal manual

National Insurance Manual

NIM31004 - Special Cases: Widows: Liability of women widowed on or after 6 April 1978: Changing to full liability during initial period

If a widow who had reduced liability as a married woman wants to have full liabilityduring the initial period of reduced liability (see NIM31003)after widowhood, she must cancel her election. The cancellation can take effect from theend of the tax week in which she tells the Department that she wants to pay full rate orfrom the end of any later week in the tax year.