Irish woman Lisa Smith, who is charged with membership of the so-called Islamic State, has won a court case fighting her exclusion from the UK.
In December 2019, an exclusion notice was served to Ms Smith by the British Home Secretary barring her from entering the UK on the grounds of public security.
Ms Smith appealed that notice to the Special Immigration Appeals Commission (SIAC) sitting in London.
The exclusion notice was based on regulations that provide for the exclusion of a national of an European Economic Area (EEA) state who is not also a British citizen.
The SIAC heard that Irish citizens can therefore be excluded, but not those with dual nationality.
Ms Smith's father was born in Belfast, and her lawyers argued that he was entitled to be treated as a dual national and by virtue of his dual nationality it would be unlawful to exclude her from the jurisdiction.
Ms Smith's mother was an Irish citizen and her parents never married.
The appeal heard that had her parents been married at the time of her birth, British citizenship "would have ensued automatically" and that it is discriminatory and a violation of Article 14 of the European Convention on Human Rights (ECHR) to treat those children of unmarried parents any differently, to those of married couples.
The SIAC ruled in Ms Smith's favour today and allowed her appeal.
Darragh Mackin, solicitor for Ms Smith, said: "Today's ruling is hugely significant for the upholding of basic human rights principles which include the right to be free from discrimination. The decision to exclude our client was discriminatory and contrary to the basic principles underpinning the Good Friday Agreement.
"As an Irish citizen who resides in a border town, it was always asserted that to restrict her from travelling across the border was unlawful and could not be stood over. We warmly welcome the court's determination today which will now reinstate our client's basic rights to travel to the North of Ireland at her convenience."