HM Customs & Excise
This site includes information about the UK's Custom and Excise Department and includes the prototype on-line VAT (Value Added Tax) returns system.
http://www.hmce.gov.uk

Inland Revenue
Responsible for the administration of income tax, national insurance contributions, corporation tax, capital gains tax, petroleum revenue tax, inheritance tax and stamp duties.
http://www.inlandrevenue.gov.uk/home.htm

The Adjudicator´s Office
Site explains the mechanism for complaining about the Inland Revenue & Valuation Office and HM Customs & Excise.
http://www.adjudicatorsoffice.gov.uk

Valuation Office Agency
Site explaining the role of the VOA in connection with council tax bands, rating assessments of non-domestic property, Capital Gains and Inheritance Tax valuations and "right to buy" determinations in the UK.
http://www.voa.gov.uk

Valuation Tribunal Service
Independent body responsible for hearing appeals concerning tax valuations. Site provides details of VTS procedures and contacts.
http://www.valuation-tribunals.gov.uk