Yulia Skripal has been discharged from hospital a month after she was poisoned with a nerve agent in the English city of Salisbury along with her Russian ex-spy father.
Medial Director of Salisbury District Hospital Dr Christine Blanshard confirmed the 33-year-old was discharged.
Dr Blanshard said: "This is not the end of her treatment but marks a significant milestone.
"We have now discharged Yulia. Both patients have responded exceptionally well to the treatment we've been providing, but equally, both patients are at different stages in their recovery."
She also said it is hoped Sergei Skripal will be able to be discharged "in due course".
Britain and its allies have blamed Russia for carrying out the attack, the first offensive use of a nerve agent in Europe since World War II, sparking a major diplomatic crisis.
The Russian embassy in London said today that any secret relocation of the Skripals will "be seen as an abduction or at least as their forced isolation".
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British Prime Minister Theresa May said the Skripals were poisoned with Novichok, a deadly group of nerve agents developed by the Soviet military in the 1970s and 1980s.
Russia has said it does not have such nerve agents and President Vladimir Putin said it was nonsense to think that Moscow would have poisoned Mr Skripal and his daughter.
The attack prompted the biggest Western expulsion of Russian diplomats since the height of the Cold War as allies in Europe and the United States sided with Mrs May's view that Moscow was either responsible or had lost control of the nerve agent.
But Moscow has hit back by expelling Western diplomats, questioning how Britain knows that Russia was responsible and offering its rival interpretations, including that it amounted to a plot by British secret services.
Mr Skripal, who was recruited by Britain's MI6, was arrested for treason in Moscow in 2004.
He ended up in Britain after being swapped in 2010 for Russian spies caught in the United States.
He lived modestly in Salisbury and kept out of the spotlight until he was found poisoned on a park bench on 4 March.