Rising in the Valley: The Merthyr Rising

Email received at Head Office from Peter Clark: On your website you quote Gwyn A. Williams's book Dic Penderyn and the Merthyr Rising stating 26 workers were killed by the Highlanders on 3rd Jume 1831.But although as you state it was an outrage against the working class to which I agree, at the inquest of one of the bystanders reported in the Cambrian newspaper of 25th June that year, 8 to 9 were killed at the scene with others later of their wounds. No proof of this number exists of such a high number as 24.You might also be interested in a current exhibition at the British Library on Propaganda.

Reply from author of the book review that originally appeared in the Socialist Standard in 1980:

People still argue about how many were killed at Peterloo, so I suppose we
should expect some disagreements.

I can't immediately find my copy of the Williams book, but there are other
websites which state that up to 24 workers were killed, eg:
http://www.martinfrost.ws/htmlfiles/nov2008/merthyr-rising-1831.html

No specific source cited, tho.