Question to the HM Treasury:

To ask His Majesty's Government what estimate they have made of the additional tax revenues that would be raised if the tax-free allowance for dividends was abolished.

HMRC publishes estimates of the direct effects of illustrative tax changes, including changes to the dividend allowance, which are available here:

https://www.gov.uk/government/statistics/direct-effects-of-illustrative-tax-changes

The additional revenue gained from abolishing the dividend allowance may not be completely scalable to the published ready reckoner because the distribution of dividend income may not be uniform and therefore scalable. Furthermore, the assumed behavioural responses may not be scalable either.