A debenture is generally taken to mean an instrument acknowledging indebtedness. They may either be issued as a single transaction or in a series of debentures, they may be secured or unsecured and may be perpetual. There is no statutory requirement for a company to keep a register of debenture holders, however if such a register is kept, it must be kept in the same manner as all the other statutory registers and available for inspection. 

In contrast in relation to charges (i.e. security interest that a company has created), since 6 April 2013 the Companies Act 2006 revised the regime for registration. Now a company that has created a charge, or any person interested in that charge, may, subject to certain exceptions deliver to the Registrar of Companies for registration a statement of particulars of that charge.  A company is therefore no longer required to keep a register of the charges it creates. There is still however a requirement for companies to retain copies of instruments evidencing registrable charges available for inspection as well as copies of instruments amending or varying any charge capable of registration. Failure to do so is a criminal offence. Note, however, that a company is under an obligation to keep a register of charges created before 6 April 2013.

Companies House must be notified of the charges within 21 days of their creation, by submitting a copy of the instrument creating the charge, together with Form MR01. This registration is primarily the duty of the company, but is frequently carried out by the debenture holder or trustee, rather than the company.