As valid as the institutional question of establishment may be, the more important factor in this pattern of decline is theological. Churches and denominations decline when they lose or forfeit their passion for the Gospel of Jesus Christ and for the Bible as the enduring, authoritative, and totally truthful Word of God. If life and death are no longer understood to hang in the balance, there is little reason for the British people to worry about anything related to Christianity. If a church is not passionate about seeing sinners come to faith in the Lord Jesus Christ, if there is no powerful biblical message from its pulpits, then it is destined for decline and eventual disappearance.
When a church forfeits its doctrinal convictions and then embraces ambiguity and tolerates heresy, it undermines its own credibility and embraces its own destruction.