If the UK leaves the EU without a withdrawal agreement, all British citizens with a Portuguese fiscal number (NIF) will have to appoint a tax representative in Portugal.
The departure of the United Kingdom from the European Union (EU) has led several Portuguese public authorities to prepare information on how British citizens should proceed in certain situations.
The AT - Autoridade Tributária e Aduaneira (Portuguese Taxation and Customs Authority) has recently published a paper dealing with the implications on matters such as income tax or customs issues.
In regards to fiscal representatives, the information provided by AT details that if the UK leaves the EU without a withdrawal agreement, British citizens with a Portuguese NIF, who have their fiscal residency in the UK or wish to move it there after Brexit are obliged to appoint a fiscal representative in Portugal.
This obligation also covers British citizens with a Portuguese NIF (fiscal number) and UK fiscal residency, who are self-employed. In this case, it's necessary to submit a change of activity statement, where the taxpayer must indicate a representative for Personal Income Tax (IRS) and Value Added Tax (IVA) purposes.
The AT also states that the VAT representative must be a VAT taxable person and have fiscal residency in Portugal.
British citizens with a Portuguese NIF, tax residency in Portugal, who are self-employed and wish to change their tax residency to the United Kingdom after Brexit must also have a tax representative in Portugal. After updating the address, they have 15 days to submit a declaration "of change of activity" where they must indicate their representative for personal income tax and VAT purposes.
You can find more information on the implications for taxpayes after the departure of the UK from the EU, in case of non-Agreement, on the Autoridade Tributária e Aduaneira’s website or schedule a meeting at Portugal Accounting’s office.