The obligation to submit annual accounts to Companies House applies to all limited companies, irrespective of their size. It is necessary for companies, whether they are engaged in trading activities, non-trading activities, or dormant, to submit their accounts to Companies House within 9 months after the conclusion of their financial year. The financial year typically spans 12 months and concludes on a specific date known as the 'accounting reference date' (ARD).

As for dormant companies, the deadline for submitting their accounts to Companies House generally falls nine months after the end of the financial year. For instance, if the financial year-end is December 31st, the deadline for filing the dormant accounts would be September 30th of the following year.

You would be required to file Dormant Company Accounts on an annual basis.