His father, John Dyer Collier (1762-1825), was a successful journalist, and his connection with the press obtained for his son a position on the Morning Chronicle as leader writer, dramatic critic and reporter, which continued until 1847; he was also for some time a reporter for The Times. He was summoned before the House of Commons in 1819 for giving an incorrect report of a speech by Joseph Hume. He entered the Middle Temple in 1811, but was not called to the bar until 1829. The delay was partly due to his indiscretion in publishing the Criticisms on the Bar (1819) by "Amicus Curiae."
His leisure was given to the study of Shakespeare and the early English drama. After some minor publications, he produced in 1825-1827 a new edition of Dodsley's Old Plays and in 1833 a supplementary volume entitled Five Old Plays. In 1831 appeared his 3-volume History of English Dramatic Poetry to the Time of Shakespeare and Annals of the Stage to the Restoration, a badly arranged but valuable work. It obtained for him the post of librarian to the Duke of Devonshire, and, subsequently, access to the chief collections of early English literature throughout the kingdom, especially to the treasures of Bridgewater House. In 1847 he was appointed secretary to the Royal Commission on the British Museum.
Collier used these opportunities to effect a series of literary fabrications. Over the next several years he claimed to find a number of new documents relating to Shakespeare's life and business. After New Facts, New Particulars and Further Particulars respecting Shakespeare had appeared and passed muster, Collier produced (1852) the famous Perkins Folio, a copy of the Second Folio (1632), so called from a name written on the title-page. In this book were numerous manuscript emendations of Shakespeare, said by Collier to be from the hand of "an old corrector." He published these corrections as Notes and Emendations to the Text of Shakespeare (1852) and boldly incorporated them in his next edition (1853) of Shakespeare.
Their authenticity was disputed by S. W. Singer in The Text of Shakespeare Vindicated (1853) and by E.A. Brae in Literary Cookery (1855) on internal evidence. In 1859 the folio was submitted by its owner, the Duke of Devonshire, to experts at the British Museum; the emendations were incontestably proved to be forgeries of modern date. Collier was exposed by Nicholas Hamilton in his Inquiry (1860). The point whether he was deceiver or deceived was left undecided, but the falsifications of which he was unquestionably guilty among the manuscripts at Dulwich College have left little doubt respecting it. He had produced the Memoirs of Edward Alleyn for the Shakespeare Society in 1841. He followed up this volume with the Alleyn Papers (1843) and the Diary of Philip Henslowe (1845).
He interpolated the name of Shakespeare in a genuine letter at Dulwich, and the spurious entries in Alleyn's Diary were proved to be by Collier's hand when the sale of his library in 1884 gave access to a transcript he had made of the Diary with interlineations corresponding with the Dulwich forgeries. No statement of his can be accepted without verification, and no manuscript he has handled without careful examination, but he did much useful work. He compiled a valuable Bibliographical and Critical Account of the Rarest Books in the English Language (1865); he reprinted a great number of early English tracts of extreme rarity and rendered good service to the numerous antiquarian societies with which he was connected, especially in the editions he produced for the Camden Society and the Percy Society.
His Old Man's Diary (1871-72) is an interesting record, though even here the taint of fabrication is not absent. Unfortunately, what he did amiss is more striking to the imagination than what he did aright, and he will be chiefly remembered by it. He died at Maidenhead, where he had long resided, on 17 September 1883.
For an account of the discussion raised by Collier's emendations, see C.M. Ingleby, Complete View of the Shakespeare Controversy (1861).
In the later 20th century, some scholars attempted a re-evaluation of Collier, defending him against the charge of forgery. The main effort was by Dewey Ganzel, in his 1982 study Fortune and Men's Eyes. In Ganzel's view, Collier's accusers, led by Frederic Madden, were motivated largely by envy and class bias; they were upper-class dilettantes determined to put down a lower-class but ferociously hard-working and talented striver. The case for Collier has relied on the fact that not all of the accusations of forgery against Collier have stood up to critical examination. (The American psychiatrist Samuel A. Tannenbaum accused Collier of forging all the accounts of the Master of the Revels, an accusation that went much too far.)
The consensus of scholarly opinion has remained convinced of Collier's guilt. Samuel Schoenbaum, in his discussion of the Collier case, mentions a damning incident omitted by Ganzel. In his old age in 1875, more than thirty years after the Perkins folio, Collier claimed in a letter to possess a John Milton folio "full of Milton's brief notes and references; 1500 of them." By this time his reputation was so tarnished that he was not able to launch another campaign of forgery, and while the "Milton" folio indeed exists (New York Public Library), the annotations are not by Milton.
A two-volume study by Arthur Freeman and Janet Ing Freeman, published in 2004, re-examines the evidence and concludes yet again that Collier was a forger.
Ganzel has written in response to the Freemans' study, "He [Arthur Freeman] assumes Collier's guilt and that leads to looking at Collier's work with the expectation of finding fraud....my study revealed what was the irrefutable evidence that he was a victim of a conspiracy of which Frederick Madden was a part...Freeman starts with a criminal; I tried to end up with a man. Freeman says that in 'suspending judgement' of Collier's guilt 'one forfeits the opportunity to explain him at all'. That confusion leads to only one kind of explanation of the events he describes, and, for me, not a very satisfactory one. The point is, the crimes are not 'unproven'; the perpetrators are."
Schoenbaum referred to an apparent confession in Collier's own diary. In the last few years of his long life, Collier expressed moments of remorse in his diary. On 19 February 1881 he wrote, "I have done many base things in my time—some that I knew to be base at the moment, and many that I deeply regretted afterwards and up to this very day." And on 14 May 1882: "I am bitterly sad and most sincerely grieved that in every way I am such a despicable offender[.] I am ashamed of almost every act of my life...My repentance is bitter and sincere[.]" Frank Kermode adds that Collier's "repentance would have been more useful if he had identified his fabrications and forgeries."
Collier has continued to have defenders. Ganzel suggested that Collier's so-called "confession" in his diary was a reference to the fact that he had not accepted certain Christian beliefs. An article in the March 2010 edition of Family History Monthly by Richard J. Westall, Collier's great-great-grandson, entitled "To forge or not to forge?" summarises the evidence and quotes a note dictated by Collier to his daughter shortly before his death: "I have written much in verse and prose, but can confidently say that I never produced a line, either in verse or prose that was calculated to be injurious either to morality or religion". Westall quotes a letter from Arthur Freeman to Westall, in which Freeman said, "we never presume JPC guilty until the evidence is sifted". Westall remarks that this "hardly squares with the disparagement made in their [the Freemans'] biography of those who 'high-mindedly' suspend judgement", stating such an approach "forfeits the opportunity to explain him at all".