Working in Brazil for a few days

Hi. I’m have dual citizenship (British and Brazilian), but I live in the UK and work for a British company. I’m going to Brazil for a short time and will be required to work from there for 3 days. I saw in the gov.uk website that a double taxation convention with Brazil has been signed but has not yet entered into force. What is the current state of this? I currently only pay tax in the UK through my employer. Would I need to pay tax in Brazil for working 3 days from there?

Hi,
The currently enforced tax treaty between the UK and Brazil , does not include rulings on employment income outside of crew of an aircraft operated in international traffic.  
agreement to avoid the double taxation of salaries of aircrew
This means that the tax treaty does not cover employment income. As there is no agreement, both the UK and Brazil will have the rights to tax your employment income. As a UK tax resident, you may be able to claim unilateral relief for any tax charged in Brazil on your earnings. 
INTM161030 - UK residents with foreign income or gains: double taxation relief: Unilateral relief
Thank you.