Hi, I agree with what Tom has already posted. It is not mandatory for locums to set up a limited company. This information may have come about from the fact that recently a large multiple have advised all their partners to ensure that any regular locums working for their stores (2-3 or more days per week) should work through a limited company. The reason behind this is in case a locum or the store has a HMRC investigation the locum/store can try and defend themselves in case the locum is deemed to be employed due to the regular pattern of work. If HMRC believes the locum should actually have an employed status, this would mean the store would be liable to make National Insurance contributions and probably there would be income tax implications. Furthermore you would be entitled to employed benefits such as holiday pay. The multiple believes working through a limited company is a loop hole to avoid this becoming an issue. The IR35 is a bit of a grey area and it probably all depends on whether someone gets investigated and how the HMRC wants to deal with it at the time. The changes to dividends from this tax year means that working through a limited company is hardly advantageous anymore as a way of reducing your tax liability especially if you are only planning on working 2 days per week. If I were you I would probably stick to being a sole trader. As Tom mentioned if you really are unsure get some professional advice.