The provisions of John Newbery's will were unfortunately somewhat complicated, and things soon began to work inharmoniously among his successors after his death.

To his son Francis he left the medicines and the medicine vending business for his sole profit; and directed that he, with his step-son, Thomas Carnan, and his nephew, Francis Newbery, should carry on the general business for their joint interest and benefit, securing proper provision for his widow and his step-daughter, Mrs Smart, wife of the poet. Young Francis, the son, was, we should imagine, from many of the records he has left behind him, a person of no small importance in his own estimation, and somewhat pompous and dictatorial in manner. These characteristics, added to the fact that he was entirely without business training and experience, led to a very uncomfortable condition of things. Immediately on John Newbery's death (in 1767), Francis, the nephew, opened a shop, and began to publish books at 20 Ludgate Street, while F. Newbery the son and T. Carnan continued at No. 65 St Paul's Churchyard. But Carnan and Newbery themselves were not on good terms; the former thought he was hardly treated by the elder Newbery's will, and that he ought to have had a larger share in the business which he had so greatly helped to make, and he, too, began trading on his own account.

No. 20 Ludgate Street is the site of the establishment at the corner of St Paul's Churchyard now occupied by the successors of the Newberys.