Nnamdi Kanu, leader of the Indigenous People of Biafra (IPOB), says he might have been killed if he did not leave Nigeria.
When he was brought to court on Tuesday, the IPOB leader said he had to leave after soldiers raided his residence in Abia state.
Kanu was facing trial for alleged treason before he jumped bail and fled the country in December 2017.
He left the court during a military operation in which soldiers clamped down on his supporters in Abia and reportedly killed some of them.
They had also besieged his residence but he eventually escaped, first to Ghana, before returning to the UK where he is based.
TheCable had reported how the IPOB leader was extradited to Nigeria after his arrest and brought to the federal high court in Abuja, where Binta Nyako, the presiding judge, granted an order for his remand.
Shortly after the ruling that he should remain in the custody of the Department of State Services (DSS), Kanu, who was without his lawyer, indicated interest to speak.
He then told the judge that the invasion of his residence forced him to flee the country.
He cited the invasion as the reason for his prolonged absence in court — despite an arrest warrant issued against him.
Nyako, the judge, then told him he should not have jumped his bail, and asked him to consult with his lawyers as the matter has been addressed.