<p>The Government’s costings of individual tax and welfare spending measures at each Budget and Autumn Statement are subject to detailed scrutiny and challenge by the Office for Budget Responsibility. Details of the costing for the policy can be found in the Summer Budget 2015 publication here: <a href="https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/443195/Policy_costings_summer_budget_2015.pdf" target="_blank">https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/443195/Policy_costings_summer_budget_2015.pdf</a></p>