Broadly speaking, if you leave the Uk permanently you stop being liable to UK tax on your worldwide income unless you return for half a tax year or 3 months a year on average. However, you never stop being liable to UK tax on your income from the UK. Depending on where you are treated as resident for tax purposes this tax year, you may claim under a Double Taxation agreement between the UK and that country to avoid being taxed in both countries. These agreements are mind-numbingly dull pieces of legislation, but they are written, by and large, to ensure you are taxed at the UK rate of tax as a minimum. You need to take professional advice about this, because the whole area is extraordinarily complicated, and it needs to be established exactly where you are resident for tax purposes this tax year. My own feeling is that you are liable to UK tax on the earnings for the 12 week period you were working in the uk.