The statistics, consulted by Lusa on Monday, show that the number of British passports issued to Portuguese nationals nearly tripled, from 165 in the third quarter of 2016 to 463 in the third quarter in 2018, according to UK’s Home Office figures.

The average number of Portuguese citizens gaining British nationality was around 500, between 2004 and 2016, but rocketed to 1,234 in 2017, an 84% increase compared to 2016.

UK residence was the reason for more than half of the processes in 2018 (669), while more than a third resulted were children (353).

The “perception of uncertainty” after the Brexit referendum, “probably contributed to the large increase in the search for residence documentation” of Europeans in the last two years, the Home Office said.

However, unless European citizens wish to apply for British nationality urgently, authorities are discouraging people from requesting the current European resident card, as the process will be replaced within two months.

The new fully digital application system for settled status will replace the need to fill out an 85-page form and complemented with dozens of documents.

The settled status will be given to those living for five consecutive years in the UK, while those living less than five years in the UK will have a pre-settled status until they complete the necessary time.

The system should only be fully functional for 3.5 million Europeans living in the UK in March 2019 and with an application deadline of 30 June 2021, if the agreement negotiated with Brussels is ratified, or 31 December 2020, if the departure takes place without an agreement.

The third phase of testing opened on Monday to all European citizens, including Portuguese, who have a valid passport and their family members who are not EU citizens but have a valid biometric residence card.