A High Court judge is to rule on whether Islamic political activist Raed Salah was detained unlawfully in Britain.
Following a two-day hearing Judge Nicol reserved judgment on whether Home Secretary Theresa May's order to arrest Sheikh Salah was legal.
The 52-year-old father-of-eight was initially detained in London in June after allegedly flouting a ban on entering Britain imposed by the Home Office.
Sheikh Salah, the leader of the northern branch of the Islamic Movement in Israel, is seeking damages for false imprisonment.
The court heard from his defence team that police officers who arrested him at a London hotel had failed to explain in Arabic why they were detaining him.
The Home Office claims officers read a section of the Immigration Act to him in English but failed to explain about the banning order.
A date is yet to be set for Mr Justice Nicol to deliver his judgment.
Sheikh Salah's full deportation hearing will take place in Birmingham on September 26.
It will decide whether he should be forcibly removed from Britain.