After Wilmot's death, his niece, Olivia Serres, claimed that he was the pseudonymous author of the famous Letters of Junius and an influential friend of major writers and politicians.
Furthermore, a document discovered in the early twentieth century appeared to demonstrate that Wilmot had been the earliest proponent of the Baconian theory, the view that Francis Bacon was the author of Shakespeare's works.
He was appointed to a curacy at Kenilworth and later promoted to the position of rector of Barton-on-the-Heath, fifteen miles from Stratford-upon-Avon, where he remained for the rest of his life and served as a Justice of the Peace.
The lectures, contained in a "thin quarto volume", were donated to the University of London in 1929 by the widow of the prominent Baconian Sir Edwin Durning-Lawrence (1837–1914) and first made public in 1932.
[7] In 2010, James S. Shapiro declared the document a forgery based on facts stated in the text about Shakespeare that were not discovered or publicised until decades after the purported date of composition.
Serres claimed that Wilmot himself was a pseudonymous author, having written the Letters of Junius, well-known Whig political tracts which defended democratic rights and freedom of speech, whose authorship had been much debated.
Serres also said that Wilmot knew the novelist Laurence Sterne and influenced leading liberal political figures including John Wilkes and Edmund Burke.
Despite this, Serres claimed to have later discovered papers written in "cyphers", which she destroyed, except for one book that contained memoranda proving "beyond contradiction" that Wilmot was Junius.
Wilmot had fathered a daughter, Olive, and had officiated at her secret marriage to Prince Henry, the Duke of Cumberland in 1767 at the London house of a nobleman.