Justin Taylor has posted a letter that J.I. Packer and several of his fellow Anglican ministers sent to Bishop Michael Ingham. The bishop threatened to strip Packer and the others of their ordination. The reason, of course, is that these men are evangelical, that is they believe the Bible to truly be God's Word and are fully committed to the true Gospel of Jesus Christ and a robust biblical faith.
When a church becomes apostate then genuine believers have no choice but to remove themselves.