(Disclaimer: not a tax expert or an accountant, but I have spent too many hours researching this stuff as it applies to my own situation.) IR35 only applies wh

(Disclaimer: not a tax expert or an accountant, but I have spent too many hours researching this stuff as it applies to my own situation.) IR35 only applies when there's an intermediary -- usually when you're providing services via a limited company, then taking dividends at the lower tax/NI rate instead of a salary. If you're self-employed and contracting with a foreign company, then IR35 can't apply (or so I was told when I spoke to HMRC to ask precisely this question). Now, HMRC could decide that it's not a true self-employment relation. In my case (self-employed, working remotely for a company in the US, limited degree of control by engager, purchasing my own equipment, bearing the risk of invoices not being paid) I think there are enough factors to make it a true self-employment relationship and HMRC's online questionnaire agrees. Even if you were contracting through a limited company, if you met the self-employment test you'd probably meet the IR35 test when operating through a Ltd. I'd prefer not to risk it -- which is why I went the self-employment route.