I seem to be developing a portfolio career - currently working two part-time jobs but have also just been asked to do a couple of bits of freelance work as well which I'm keen to build up in the longterm.
How does this work? I am paid through PAYE with all my tax, NI deductions etc in my current jobs, and am over the £10k tax threshold.
Do I need to register as self-employed and do my own tax return as well? (we're talking a few hundred pounds through freelancing at the moment, not thousands!) Is there anything else I need to think about?
Yes, you need to register. You then do a self-assessment tax return, which has sections for income from employment and self-employed profit as well. They then work out how much tax you need to pay over and above any you've already paid via PAYE.
The advantage with being self-employed is that if you are using a room in your house for work, or even a desk and computer in the corner, you can claim a proportion of certain household bills as business expenses, and deduct that from your self-employed income. Keep all receipts for stationery, postage etc as well. Depending on your working arrangements you might also be able to recover part of your vehicle costs too.