"If there is no deal, in that situation I am sure that the United Kingdom will fulfil all of its obligations to European citizens, inluding the Portuguese," ambassador Manuel Lobo Antunes, told Lusa.

In September, following an informal meeting in Salzburg, UK Prime Minister Theresa May, said negotiations had come to a stalemate and that it was possible no deal would be reached, but gave assurances that the rights of Europeans would be respected.

Antunes said May's words, "added to what had already been said on other occasions and what other members of the government have said."

This is why, he said, there have been "intense contacts" with the UK Home Office to prepare a new system for registration of resident status, which is expecetd to be in place on 30 March, 2019.

This new system, which will replace the current one requiring dozens of forms to be filled out and numerous documents to be sent, will be entirely online and cross-reference database information from the tax and social security authorities.

Settled status will be granted to people living for five consecutive years in the United Kingdom while those who ahve been living in the UK for less than five years will receive provisional pre-settled status until they reach the time required for settled status.

Including a transtional period until the end of 2020, outlined in a preliminary agreement reached in December 2017, EU citizens will be allowed to circulate freely in the UK and settled status can be requested until 30 June 2021.

However, without an agreement, the rules for citizens who want to settle in the UK after Brexit becomes official, on 29 March, 2019, are still not clear, the Portuguese ambassador said.