The Church of England faced increasing external challenges in the Victorian period. It also suffered serious internal divisions. How it sought to contend with these problems can be usefully addressed through a study of the London Union on Church Matters (LUCM). The LUCM represents an effort by High Churchmen to uphold Church interests and promote a particular idea of what the Church should be. Historians have not previously paid it much attention. There is no LUCM archive, but the opinions and activities of the body can be recovered through contemporary books and periodicals, the correspondence, speeches, and writings of its leaders, parliamentary proceedings, and various Church records. The LUCM placed itself at the head of a wider church union movement, which lasted from the 1840s into the 1860s. Unions condemned unwelcome legislative interference in Church concerns and rejected the claims of Liberal politicians and assertive Nonconformists. They resisted attempts by the Low Church party and Evangelicals to guide the Church in a direction that was unacceptable to High Churchmen. The movement could not remain united, however, for another body was formed in London, the Metropolitan Church Union, and on some issues it refused to accept the LUCM’s directing and coordinating role. This had implications both for Church defense and for the High Church agenda within the Church of England. There was no consensus about how to promote either cause.