What is the UK GDP Report

The UK GDP report is released once per quarter, approximately 3 weeks after the
end of the quarter. The UK GDP Report, or Gross Domestic Product Report measures
the total value of goods and services that were produced/provided within the UK
after deducting the costs for proudction.

GDP is calculated based on the following formula:
Consumer/Private Spending [...]

http://www.ecnforex.co.uk/what-is-the-uk-gdp-report/