In May 1921 William commenced a united mission in Portadown; this mission had wide support from all the local churches. The meetings were held in the First Presbyterian Church for the first two weeks then in Thomas Street Methodist Church for the final two weeks. The commencement of the mission was delayed for a week because of the great coal strike combined with a dock strike which delayed William's crossing from Glasgow. The Belfast Telegraph interviewed William when he was eighty-two years old and William laughed as he recalled the beginning of the mission. "We were very fortunate, for there was a shortage of coal and the people of Portadown were kept warm in my mission hall."
The church was packed to capacity for the first two weeks, and this was repeated in the second half of the mission held in Thomas Street Methodist Church. A report of the mission which appeared in The Irish Endeavour in July 1921, states:
Mr Nicholson gained the ear of the people in a marked degree, and although uncompromising in his condemnation of smoking and dancing and the picture show, and presenting the bald alternatives of "Christ or Hell," even those who disagreed with him came under his spell and were converted. Over 900 names were registered as of those accepting Christ and whole families became one in Him.
From 'All for Jesus' by Stanley Barnes, published by Ambassador Productions, p62-3
1845. Early in the year Mr William Pattyson of the Primitive Wesleyan Society writes, giving a cheering account of the work on his circuit, which had been favoured with a continuous outpouring of the Holy Spirit for about twelve months. The quarterly meetings at Tanderagee, Derryanvil, and Portadown had been times of remarkable power, and at the subsequent prayer meetings there were many earnest seekers of salvation. Altogether, during the year upwards of three hundred persons, old and young, parents and children, were brought. from darkness to light, and from the power of Satan to serve the living God.
'History of Methodism in Ireland', Volume iii, by Crookshank, p358.
1858. In autumn a remarkable seriousness was observed to pervade not only the Wesleyan Methodist congregations of Portadown but those of other denominations. Revival services were held by the Rev. Robert Hewitt and were much owned of God, leading to the conversion of R. Crawford Johnson, Anthony Cowdy, and many others. The classes were increased, and a general quickening was manifest. A meeting for inquirers held each Monday evening also proved the means of much good. Through all this there were none of the young men of the congregation who appeared so uninfluenced or unapproachable as Thomas Shillington (2nd), and one of his cousins, until one Sunday evening, after service, as they walked together, the younger of the two abruptly said, "I have been saying to myself, but I did not care to say it to you, that if ever we are to get religion it's time we were thinking of it." This simple statement, accompanied by the Holy Spirit, proved more effective than all the sermons to which these young men had listened, leading them to resolve to turn to God. Both attended the inquiry-meeting on the following evening, and some time afterwards each obtained a clear evidence of pardon and acceptance with God.
'History of Methodism in Ireland', Volume iii, by Crookshank, p498.