This aspect of his persona was portrayed extremely well in the recent movie "Amazing Grace" which was about William Wilberforce's role in the abolition of slavery in the British Empire. The actor who played Tarleton, Ciaran Hinds, did an outstanding job, just as he did in his role as Julius Caesar in the HBO/BBC television series "Rome".
I LOVE that show; Hinds’ portrayal of Caesar may be the best by anyone, ever.