Stephen Tomkins’ gift seems to be irony and the ability to prick the halo bubble around saints, which he did with John Wesley but does a little less directly in his book William Wilberforce: A Biography.

Wilberforce was exposed to evangelicalism of a Wesleyan sort very young but it concerned his mother, she drew him back into her own orbit of aristocratic friends, and Wilberforce then naturally evolved into a well-to-do, gentlemanly, gambling, quiet church goer with enormous political influence in all of England.
But he found true Christianity. He devoted his life to Bible reading, to prayer, and to a concentrated effort to extinguishing slave trade and slavery. He was also a moral activist, trying to get England more in line with Christian living, but it is his anti-slavery speeches and activism that have led to his powerful reputation. (Tomkins does not hesitate to point out his faults, but he’s not as hard on Wilberforce as on Wesley.)
What impressed me most about this book is the tireless work — and it took two decades — to get anti-slave trade laws passed. Wilberforce never gave up; and he was the right man at the right time to get the right job done. He was not alone, of course, but he was a central figure in the center of the storm.