His Majesty's Revenue and Customs (HM Revenue and Customs or HMRC) is responsible for the collection of taxes and the payment of some forms of state support.
The numbers for HMRC are listed below, HMRC also provide online resources to assist taxpayers with their tax problems - here you can find their online support for self-assessment.
Have your National Insurance number with you when you phone.
Open: Mon to Fri: 8am to 8pm, Sat: 8am to 4pm
Closed: Sundays and bank holidays.
Phone lines are less busy before 10am, Monday to Friday.