Her Majesty’s Revenue and Customs (HM Revenue and Customs or HMRC) is a non-ministerial department of the UK Government responsible for the collection of taxes, the payment of some forms of state support, and the administration of other regulatory regimes including the national minimum wage.
Link to HMRC
Companies House incorporates and dissolves limited companies, registers the information companies are legally required to supply, and makes that information available to the public. There are more than 3 million limited companies registered in the UK, and 500,000 new companies are incorporated each year.
Link to Companies House