A radical Muslim cleric banned from his local mosque was allowed to work as a hospital chaplain, according to a BBC London investigation.
Mr Ali is a former member of the now banned Al Muha-ji-roun
Usman Ali has been banned from his local mosque in Woolwich, London, after trustees won a court injunction.
But the ex-member of banned group Al Muha-ji-roun led prayers for NHS staff at Woolwich's Queen Elizabeth Hospital.
Hospital staff said they had suspended Mr Ali two days ago after concerns were raised by the police.
Banned for life
The 30-year-old British born preacher was banned for life from entering his local mosque in Woolwich after trustees won a county court injunction against him in January.
It was an unprecedented step and cost the mosque £30,000.
BBC London has seen the judge's order on the case and found that Ali had shown a video to children in the mosque containing clips of planes flying into the world trade centre during which he chanted "God is great".
Mosque trustees said they warned hospital officials about Mr Ali months ago but nothing was done.
However, a hospital spokesman said: "We had no allegations made about this man's behaviour but as soon as the police raised their concerns we took action."
Mr Ali declined requests for an interview.