Accountancy Service Providers (ASPs): What does an ASP do?
You should check the other guidance available on GOV.UK from HMRC as Brexit updates to those pages are being prioritised before manuals.
There is no simple answer to this. Although it is possible to break down the functions of an ASP into several distinct activities, some ASPs will perform several of these functions. For example an accountant may provide tax advice, payroll services and bookkeeping in addition to accountancy. Some businesses however specialise in just one branch of the profession. This is frequently the case with bookkeepers and stocktakers.
There is sometimes an overlap between the activities carried out by an ASP and a Trust or Company Service Provider (TCSP) and some have dual registration for MLR purposes.
The work of an ASP is also determined by the services that the client requires. A substantial business may have its own in house accounting section which carries out the bookkeeping, operates the payroll and files its own VAT returns. It only requires the service of an ASP to prepare its annual accounts and submit its tax return to HMRC. On the other hand a sole trader with little or no accountancy skills may require a full range of services.