George Julian Harney (1817–79) was a journalist and Chartist leader radicalised in his youth as a result of being imprisoned on three occasions for selling the unstamped Poor Mans' Guardian.
He became a Chartist leader and the editor of Feargus O'Connor's Northern Star and persuaded both Karl Marx and Friedrich Engels to write articles for the paper.
He emigrated to the USA in 1863, working as a clerk in Massachusetts for fourteen years. He returned to England after his retirement.
Harney died in Richmond and his wife Mary (née Cameron) erected this (vandalised?) monument, which calls him 'The last of the Chartist leaders' and remembers 'many years of happy wedded life'.
My other posts on graves in East Sheen and Richmond cemeteries are linked below: