Assange, 45, took refuge in the embassy in June 2012 to avoid extradition to Sweden after two women made rape and sexual molestation allegations against him, which he denies.
He feared Sweden would hand him over to the United States to face prosecution over WikiLeaks' publication of swathes of classified military and diplomatic documents in one of the largest information leaks in U.S. history.
Assange tweeted on Friday that he would not forgive those behind the investigation: "Detained for 7 years without charge while my children grew up and my name was slandered. I do not forgive or forget."
Earlier Swedish Chief Prosecutor Marianne Ny said the rape investigation could not proceed because of legal obstacles.
"We are not making a statement about his guilt," Ny said, adding that the investigation could be reopened if Assange came to Sweden before the statute of limitations deadline for the rape allegation in 2020.
However, police in London said they were still obliged to arrest Assange if he left the embassy for skipping bail.Read more at Reuters