In 1801 Montagu published "A Summary of the Law of Set Off, with an Appendix of Cases argued and determined in the Courts of Law and Equity upon that subject", London, on an intricate branch of the law; and between 1805 and 1807 compiled "A Digest of the Bankrupt Laws, with a Collection of the Cases argued and determined in the Courts of Law and Equity upon that subject", London, 4 vols. In 1809 he published "An Enquiry respecting the Expediency of Limiting the Creditor's power to refuse a Bankrupt's Certificate", London; in 1810 an "Enquiry respecting the Mode of Issuing Commissions in Bankruptcy", London, a protest against the practice then in vogue of initiating bankruptcy proceedings by means of secret commissions; and in 1811 "Enquiries respecting the Administration of Bankrupts' Estates by Assignees", London.