RUSSIA has warned Britain that it is "playing with fire and will be sorry" over the Salisbury poisoning as the war of words between Moscow and London continued.

The blunt warning came as Viktoria Skripal, the cousin and niece to Yulia and Sergei, suggested the UK authorities would deny her visa request to visit Britain to see her relatives, who are still recovering from the poisoning incident in Salisbury last month.

Ms Skripal told Sky News that the British Embassy in Moscow had told her it was up to the authorities in Britain to decide whether or not to let her in but she said she was "pretty sure" they would not.

In contrast, she pointed out how the Russian authorities had been "very helpful" and wanted her to see her relatives.

Ms Skripal insisted she was "trying to remain neutral" over where the fault lay in the diplomatic row until she knew more facts about what had happened.

At the United Nations in New York, the two countries referenced British dramas and the Nazis as they traded jibes with the UK arguing that doubt should not be cast on the likelihood of Russian responsibility for the Novichok nerve agent attack and that British actions "stand up to any scrutiny".

But Vasily Nebenzya, the Russian ambassador to the UN, pointed to Midsomer Murders and read from Alice's Adventures In Wonderland to mock suggestions of Russian involvement.

He claimed the UK's main argument about the "unquestionable Russian origin" of the Novichok was "no longer valid" following comments from Porton Down's Gary Aitkenhead.

Later, Mr Nebenzya accused the West of "using the method of Dr Goebbels; lies that are repeated a thousand times become the truth" by trying to manipulate people via the media.

The terse exchanges at the UNSC capped another 24 hours of developments and diplomatic disagreements, which saw the first public comments emerge from Yulia Skripal since the March 4 attack which left her and her father Sergei in hospital intensive care.

Ms Skripal's remarks were released shortly after Russian TV reported that she had contacted a relative in Moscow to say she and her Russian spy father were recovering and that she would soon be discharged from hospital.

Moscow called the UNSC meeting to discuss the incident, with Sergey Lavrov, its Foreign Minister, saying the UK had "legitimate questions" to answer about what happened.

But Ben Wallace, the UK Government’s Security Minister, said it was "beyond reasonable doubt" that Russia was to blame for the attack.

A 90-minute press conference at the Russian embassy in London also saw ambassador Alexander Yakovenko repeat Moscow's denial of responsibility for the attack.

On Wednesday, Russia lost a vote at the Organisation for the Prohibition of Chemical Weapons [OPCW] in The Hague on its demand for its experts to be involved in testing samples of the substance used in the Salisbury attack.

Ahead of the UNSC meeting, Karen Pierce, the UK ambassador to the UN, told reporters: "Allowing Russian scientists into an investigation when they are the most likely perpetrators of the crime in Salisbury would be like Scotland Yard inviting in Professor Moriarty, so I don't think that's a tenable way forward."

But Mr Nebenzya said characters in Midsomer Murders knew "hundreds of very clever ways of killing someone" but those who sought to kill the Skripals "supposedly chose an extremely toxic chemical substance, the most risky, dangerous method possible" and "didn't really finish the job".

Kelley Currie, US representative on the economic and social council at the UN, said: "Our support for the United Kingdom is unwavering and we continue to stand in absolute solidarity with our British colleagues."

Yulia Skripal brpke her silence to say she was recovering and that her "strength is growing daily". It has been suggested she could be discharged within days. Her father, Sergei, however, remains in a critical condition.

Elsewhere, The Times reported that British intelligence had pinpointed the source of the Novichok nerve agent used in the Salisbury attack as a military research base at Shikany in southwest Russia.

Hamish de Bretton Gordon, the former commander of Britain’s Chemical, Biological, Radiological and Nuclear Regiment, has seen the intelligence and described it as very compelling.

“The intelligence Britain has clearly points to Russia and Shikhany. No doubt the Russians are scrubbing it down as we speak,” he said.