Julian Assange had two children while living in the Ecuadorian embassy in London, it was revealed.
Their mother, lawyer Stella Morris, had helped the Wikileaks founder fight extradition to the United States, where he faced espionage charges for the leakage of thousands of secret intelligence documents.
Assange has been imprisoned in the high security Belmarsh prison since he was dragged out of the embassy, where he had sought political asylum for seven years, last April.
He now awaits an extradition hearing on May 18.
Her two children Gabriel and Max were born in secret, but Miss Morris has now spoken out because she fears that her partner’s life is at risk if she stays in Belmarsh during the coronavirus pandemic, reports the Mail on Sunday.
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Saying that there are genuine fears for his health, he launched a release request for the deadly insect to spread to the UK prison population.
The controversial Wikileaks boss is said to suffer from chronic lung disease, and his friends say that a Belmarsh prisoner has already died of Covid-19, while a number of officers are suspected of having the virus.
Miss Morris, 37, says she also suffers from mental health problems that make him vulnerable to isolation.
In a court statement in support of an application for bail, the Swedish lawyer revealed that he met Assange in 2011 when she was a legal researcher.
“Over time Julian and I have developed a strong intellectual and emotional bond. He has become my best friend and I have become his,” he wrote.
Friendship developed and, despite “extraordinary circumstances”, a close relationship began in 2015, he said.
The couple have been engaged since 2017, the year in which their first son Gabriel was born.
Their second, Max, was born in February 2019 and his birth was filmed with a GoPro so that his father could watch the footage.
Miss Morris added that she did everything she could to protect the children from the climate surrounding Assange.
“My close relationship with Julian has been the opposite of how it is viewed – reserve, mutual respect and attempts to protect each other from some of the nightmares that have surrounded our lives together,” he said.
He said he was revealing their relationship now because their lives were “on the verge” and he feared that his fiancée might die.
He is in solitary confinement for up to 23 hours a day and all visits have stopped, he added.
Speaking on Sunday post, Miss Morris says she is “terrified” that she won’t see Assange alive anymore.
“I love Julian deeply and can’t wait to marry him,” he said.
“I lived quietly and privately, raising Gabriel and Max alone and wishing the day we could be together as a family.”
He added: “Julian’s poor physical health puts him at serious risk, like many other vulnerable people, and I don’t think he will survive coronavirus infections.”
Assange’s legal team had tried to get an update of his extradition hearing, claiming that the Covid-19 pandemic had created “insurmountable” difficulties in preparing his case, but this was dismissed by a court.
If found guilty of the US charges, he could face 175 years in prison.