REPORT: The UN thinks Julian Assange is being unlawfully detained
The publisher and founder of Wikileaks has been living in the embassy since 2012. He was granted political asylum there after Sweden attempted to extradite him to question him over sexual assault and rape allegations.
Assange maintains that if he goes to Sweden, he will subsequently be extradited to the US to stand trial for his work on Wikileaks.
A UN Working Group on Arbitrary Detention has been investigating Assange's case following his complaint in 2014 that is being "arbitrarily detained."
This week, he said that if the group said he was not being detained, he would leave the embassy voluntarily and surrender himself to British police.
But the BBC reports this will not be the case. The British broadcaster says it "understands" that the panel has ruled in his favour.
So what happens now? Prior to the BBC's report, Assange said in a statement that "should I prevail and the state parties be found [by the UN panel] to have acted unlawfully, expect the immediate return of my passport and the termination of further attempts to arrest me."
However, the UN Working Group does not have any binding legal powers. Its ruling may be influential in the long run - but Assange will not be able to leave the embassy a free man on Friday like he hopes.
For now, Wikileaks' official Twitter account has acknowledged the report, and says the group is "waiting [for] official confirmation."
Some of the allegations facing Assange were dropped in 2015 because the Swedish statute of limitations expired. However, the more serious allegations of rape will not expire until 2020 - meaning that if Swedish prosecutors do not drop their investigation, and Assange does not surrender himself willingly, he could remain in the embassy for another four years.
Meanwhile, Assange's health is continuing to deteriorate. His doctor says that the Wikileaks publisher is in "constant and severe pain," and needs an MRI scan to help with diagnosis - a procedure that cannot be carried out in the embassy.
UK authorities have refused to grant Assange "safe passage" to a hospital for the scan.