Lawyers for Babar Ahmad will tomorrow fight tooth and nail to halt his extradition to the United States to face terror charges.
They are to seek a judicial review in a bid to scupper Home Secretary Theresa May's plans to send Mr Ahmad - who has spent eight years in jail without charge - to the US.
A Territorial Support Group squad snatched Mr Ahmad from his bedroom in Tooting in a violent 2004 dawn raid.
Intelligence officers accuse Mr Ahmad of raising funds for terrorist organisations through websites - operating from London but hosted in the US - supporting Afghan and Chechen fighters.
Crown prosecutors have said there is "insufficient evidence" to charge Mr Ahmad with any offence under British law - yet controversially do not require the US government as an extradition partner to provide any evidence at all.
But tomorrow's eleventh-hour bid could be all that stands between Mr Ahmad and US interrogators after judges in Strasbourg last week cut off his only avenue for appeal in the European Court of Human Rights.
The Home Office said in a statement following last week's ruling it now intended to hand over Mr Ahmad and four others - including radical preacher Abu Hamza - "as quickly as possible."
Mr Ahmad's family said in a statement that they were only asking the court to give crown prosecutors time to consider the evidence properly.
One supporter, Newcastle businessman Karl Watkin, had even launched a private prosecution of Mr Ahmad and fellow suspect Syed Ahsan to ensure he was tried in Britain on the available evidence.
But director of public prosecutions Keir Starmer said the documents provided were "very short, lack any meaningful detail and do not provide any real support for a prosecution."
President of the Queen's Bench John Thomas and Mr Justice Ouseley are to preside.