I don't think the UK revenue need to take a test case to court. In the UK, tax is the only area where you are guilty, until you can prove yourself inocent. In other words, if they decide to give you a tax demand for your earnings from Brookfield, You have to either pay up, or prove to them you don't owe it. If you can't pay, they just take your house, furniture, car and anything else they can sell!