Because of how the tax year runs in the UK you can work out how much tax you will owe if you come out here in january. Because the tax you pay is based on your annual salary if you are not working in the uk January through April you will pay lower tax for the tax year! If that makes sense - and sometimes you are entitled to tax back if you don't work the whole financial year. You will have to fill in a non-resident form to say you will not be earning in the country. Phone your local tax office, explain your situation and they should be able to help you.