Managed Service Companies are described by the HMRC as a company that provides the services of individuals to third party clients and are involved in their business. By "involved" this is usually by benefiting financially from the provision of those services to clients and/or influencing or controlling the provision of services or the way in which the payment for services is made. (In other words the contractor is not in business on their own and does not have full responsibility and control over their business as this is done by a service provider on their behalf)
The managed service company legislation was brought into place by HMRC in April 2007 and applies to all individuals providing their services through a limited company. If a contractor was to use a company that would be classed as a MSC under the legislation then all payments they receive would be subject to PAYE tax and national insurance contributions as if they were a normal employee.
No we do not, HMRC guidance states that an accountant or tax adviser who provides advice to clients who are service companies is not an MSC Provider if the client is in business on their own and not under control of their accounting provider