Mr Kanu alleged that officials of the State Security Service (SSS), where he is being detained, did not allow him to file the process in his defence.
This story was updated with more accurate details of what transpired in court, leading to a brief pause to allow Mr Kanu to make the filing he requested.
The Federal High Court in Abuja, on Friday, stood down proceedings to allow Nnamdi Kanu file the process and depose to an affidavit in his defence in the ongoing terrorism trial.
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Justice James Omotosho stood down the matter after the prosecutor, Adegboyega Awomolo, applied for a stand down to allow Mr Kanu file the document.
The development occurred shortly after the case was called, and Mr Kanu, leader of the proscribed Indigenous People of Biafra (IPOB), alleged that officials of the State Security Service (SSS), where he is being detained, did not allow him to file the process in his defence.
"My lord, I don't know how to say this. I have a process here to file, which has not been allowed for the last three days.
"I have the process for my defence. I don't know if my lord will allow me to file it for my defence," he prayed.
Justice Omotosho then sought a response from the SSS officers in court on why Mr Kanu had not been allowed to file the document.
One of the operatives of the security agency stood up and addressed the court.
The officer said after the adjournment on Wednesday, Mr Kanu told them that he wanted to file a process.
"We waited for him (Kanu) and he could not file the process, and we left," he said.
He said on Thursday, they got information again at the office that Mr Kanu wanted to file the process.
He said if the defendant wants to file a process in court, they have a standard procedure and protocol for Mr Kanu's movement to guarantee his safety and the safety of others around.
He explained that a letter ought to be written by his former lawyers, who are now consultants, to the SSS management before he could be allowed.
"We only got the information from our officers who are detailed to him. So that creates a logistic problem," he said.
Also responding, Mr Awomolo said the protocol for Mr Kanu's movement is dictated by the court's order.
"However, we will ask for a stand down for about an hour my lord to allow him file the process," he said.
However, Mr Kanu disagreed with the SSS officer on his submission.
"What he just narrated was not correct," he said.
"When I was downstairs looking for the process on Wednesday, they (the officers) said let us go and you will be brought back the next day," he said.
Mr Kanu alleged that he had also told the SSS officers that the court officers could be allowed to bring the stamp for him to depose to the affidavit, but they refused.
Mr Awomolo then said that the issues, as difficult as they seemed, could be made easier by Mr Kanu's legal consultants.
He said he was not aware that Mr Kanu planned to file a process.
"I was not aware of this. If they (consultants) can talk to me or the Legal Department at the DSS, they are their colleagues, the matter would have been resolved.
"They can speak to them (Legal Department). They (the consultants) equally have my phone number; they can call me," Mr Awomolo said.
The judge, who stood down the matter, ordered the officers at the court registry and the commissioner for oaths to come into the court with the stamp to attend to Mr Kanu.
"The defendant will file here while we take other matters," the judge said.
Justice Omotosho further made an order allowing the court workers to go to the SSS office with the court stamp whenever Mr Kanu is a deponent to a document.
Mr Kanu, who was expected to open his defence today, is standing trial on alleged terrorism offences.
The Trial
PREMIUM TIMES reports that the judge had, on Wednesday, given Mr Kanu the last chance to open his defence, a scenario that had repeatedly played out in the previous month in the case.
The Nigerian government has been prosecuting Mr Kanu on seven charges, mostly terrorism-related, since 2015.
The charges stemmed from his alleged violent secessionist campaigns for the independence of the Igbo-dominated South-eastern part of Nigeria as Biafra.
But the dual Nigerian and British citizen has repeatedly denied wrongdoing.
The prosecution closed its case with five witnesses in June.
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After the prosecution closed its case, Mr Kanu filed a no-case submission, arguing that the prosecution failed to lead credible evidence against him to warrant putting forward any defence.
However, in September, the judge dismissed the no-case submission, ruling that he had a case to answer and should enter his defence.
Since then, several proceedings have been scheduled for him to start his defence after he suddenly disengaged his lawyers and told the court that he would defend himself.
The case was adjourned several times in the past month to keep the window of defence open, while Mr Kanu continued to maintain that there is no valid charge against him to defend.
He argued that the charges against him "were brought under a repealed terrorism law."
Following Mr Kanu's insistence that the charges were invalid, the judge, Mr Omotosho, on Wednesday, reminded him of the need to keep his "gun powder dry" for his defence.
Mr Kanu said he would need to consult with his four legal consultants, whom he named as Nnaemeka Ejiofor, Aloy Ejimakor, Maxwell Okpara and Mandela Umegborogu, after which the case was adjourned to Friday (today).
