All UK companies must file annual accounts.
There are allowances on the timing of the submission on the first year of accounts, typically these are where the start date is mid calendar and is for the purposes of synchronising the year end with that of the parent. For future years statutory accounts must be filed within nine months of the year end with Companies House.
The quantity and detail required for Statutory accounts depends on the size of the company, ie small, medium or large. There are various guidelines for determining the size category based on a combination of the number of employees, revenue and net assets.
Other statutory reporting considerations are for VAT (quarterly), Corporation Tax returns (annual) and Companies House returns.
Audit requirements vary considerably by company and industry, typically audits are conducted by the audit firm of the parent using their own local firm or a partner firm. UK audits for subsidiaries are normally an extension of the work they do for the parent entity.