The self-employed pay their own tax, but employees have their employers pay it for them. If you make a mistake in classifying somebody, the money’s gone, and you may well find yourself paying out twice.
Getting the classification right is not always easy: there are myriads of little tests of varying degrees of importance. David Kirk’s book Employment Status – the Tax Rules [link to section about book on this website](available from Claritax Books [link to http://www.claritaxbooks.com/books/employment-status-the-tax-rules/]) provides the answers, and is actually shorter (293 pages) than HMRC’s Employment Status Manual (349 pages). Quicker still, why not ring us up and ask?