The revisionism which has marked the secularisation debate in recent decades has modified in various respects the traditional view that Christianity in Britain has been in almost constant decline for at least the last century or so. As a contribution to the debate, this article revisits the changes which developed in the internal dynamics of English and Welsh Nonconformity during the period from about 1850 to 1930. It argues that the secularisation of Nonconformity at the institutional level was primarily due to the fact that it became more associational and less communal in character. Indeed, Nonconformist Churches almost certainly contained the seeds of secularisation from their inception, as they were the first widespread voluntary associations in Britain with the concept of formal membership.