the process of claiming tax credit through a DTA is well known. If your tax credit doesn’t cover your Thai tax liability you will be paying additional Thai tax. A basic rate UK tax payer pays 20%, Thailand has tiered rates up to 35%. Its follows that a Thai tax liability can occur on foreign sourced remitted income that has already been taxed in the source country.
Anonymous participant you can work remotely as long as you don’t work for a Thai business or have any Thai customers. The company, customers and payments must all be outside of Thailand.
Anonymous participant Thailand does not tax worldwide income. Working remotely on a DTV is NOT earning Thai sourced income. On many DTV visas you will see printed “Employment Prohibited “. You are not allowed to earn Thai sourced income with a DTV.