Unforeseen and far-reaching consequences followed hard upon the opening of this place of worship.  The Rev. W. Sellon, incumbent of St. James, Clerkenwell, the parish in which the new chapel stood, was a pluralist, holding no less than four ecclesiastical appointments, yielding him in all L1500 a year.  Destitute himself of any knowledge of or sympathy for Gospel preaching, he resented this attempt to feed “the hungry sheep” of his parish.  He invoked the law against Mr. Jones and Mr. Taylor, both clergymen of the Established Church, who were conducting the services at Spa Fields with conspicuous success.  Sellon claimed the right of preaching in Spa Fields whenever he wished, and asserted his right to all the moneys derived from sittings and other sources.  He obtained a verdict in the Consistorial Court inhibiting Jones and Taylor and closing the church.  To meet this state of affairs, Lady Huntingdon acquired the building in her own right, changed the earlier name of Northampton Chapel into Spa Fields Chapel, and appointed Dr. Haweis, one of her chaplains, to preach.  Sellon again applied to the Ecclesiastical Courts, and obtained an inhibition prohibiting any clergyman of the Established Church, whether Lady Huntingdon’s chaplain or not, from preaching in Spa Fields.

Lady Huntingdon rose to the occasion.  She was not the woman to allow an altogether unworthy opposition to defeat what she felt to be God’s work.  Since the law upheld Sellon, she in her turn invoked it.  Under the Toleration Act she claimed and exercised her rights.  “I am reduced,” she wrote, “to turn the finest congregation, not only in England, but in any part of the world into a Dissenting meeting.”  Mr. Wills and Mr. Taylor, two clergymen who were prominent at this time among the Countess’s helpers, both determined to secede from the Established Church; and thus once and for ever she disposed of Mr. Sellon’s claims and prerogatives.  Mr. Wills became the regular minister of the church.  It was in this building that the first annual sermon of the London Missionary Society was preached by Dr. Haweis, and for over a hundred years Spa Fields Chapel was a centre of light and help and healing for that part of London.

This legal conflict had placed those numerous and able clergymen who had been in the habit of preaching in Lady Huntingdon’s chapels in a very awkward position.  They had to choose between two masters.  Not unnaturally they remained in the Established Church.  Hence from 1779 Romaine, Venn, Jones, and many others, though still in full sympathy with the Countess’s work, ceased to preach in her chapels.

The students educated at Trevecca now rendered services of great value.  In addition to their itinerating labours, they gradually filled the pulpits thus left vacant in the chapels.  Hitherto the great majority of them had sought ordination in the Church of England, such having always been Lady Huntingdon’s desire for them.  This being no longer possible, the first public ordination of Trevecca students took place at Spa Fields March 9, 1783, when Mr. Wills and Mr. Taylor ordained six young men to the work of the ministry.  It was on this occasion that the well-known Fifteen Articles, subscription to which became essential for entrance into the college, or into any of the pulpits under Lady Huntingdon’s control, were first publicly read.