The Government has made no estimate of the impact on income tax receipts of raising the top rate of income tax to 50 per cent.
The forecast Exchequer revenue effect of the change in the top rate of income tax from 50 pence to 45 pence is as follows:
The revenue effects detailed above are set out in the 2013 Budget document, available at;
The HMRC report “The Exchequer effect of the 50 per cent additional rate of income tax” details the rationale for the rate change. The report is published and available at: http://www.hmrc.gov.uk/budget2012/excheq-income-tax-2042.pdf.
This was recently endorsed by the independent Institute for Fiscal Studies.