Yulia Skripal has been discharged from hospital more than a month after she was poisoned by a military-grade nerve agent together with her father, a former Russian spy, the English hospital treating them says.

Russia tells Britain at the United Nations Security Council that "you're playing with fire and you'll be sorry" over its accusations that Moscow was to blame for poisoning a former Russian spy and his daughter.

Yulia Skripal, who was poisoned with a nerve agent in an English city last month along with her Russian ex-spy father Sergei, says she is recovering, according to a police statement issued on her behalf.

The daughter of former Russian spy Sergei Skripal, who with her father was poisoned with a nerve agent in Britain earlier this month, is no longer in a critical condition and is improving rapidly, the hospital treating the pair says..