In the 1860s over a million people were added to the church. United prayer seemed to be the spark. This is what happened in Hull:

“There were united daily prayer meetings in the port city of Kingston upon Hull, supported by the established church and the dissenting denominations. Numbers of people were unable to gain an entrance to the central meetings, and so, many places of worship were opened each evening for prayer. A monthly united prayer meeting attracted more than 3000. As usual a rising tide of evangelism followed, and campaigns were still crowding halls in 1865 to excess, necessitating the hiring of the circus, at which ministers of different denominations preached. Other very successful campaigns were carried on throughout the year 1865.”

Taken from the Second Evangelical Awakening in Britain by J Edwin Orr