If you listen to or read Chuck Colson's BreakPoint commentaries, you've probably heard him speak frequently about William Wilberforce. The Wilberforce Forum is a division of Prison Fellowship. Here's a description of this division from their web site (you can follow the links for more information on Wilberforce and the Forum):
The Wilberforce Forum is a division of Prison Fellowship. Our goal is to help Christians approach life with a biblical worldview so that they can in turn shape culture from a biblical perspective. Using the talents of leading Christian thinkers and writers, we seek to help Christians think and live Christianly not only in church and family circles, but also in the public square.
We take our name from Britain’s great eighteenth-century reformer, William Wilberforce, who fought for twenty years in the House of Commons to abolish the slave trade. Because of his love for Christ, he dedicated himself to fight for the freedom of those who could not speak for themselves. Wilberforce sought, as well, to reform the morals of his nation, and his influence helped to lead England into the great nineteenth-century revivals. He exemplifies the Christian’s role in society and provides a model for our endeavors in The Wilberforce Forum.