Russian President Vladimir Putin has placed his nuclear forces on high alert, alarming the rest of the world. According to the Federation of American Scientists, Russia possesses a total nuclear weapon inventory of 5,977, making it the world's biggest.

According to the Bulletin of Atomic Scientists, Russia has 4,447 warheads in its arsenal, with 1,588 of them deployed on ballistic missiles and heavy bomber bases. "Approximately 977 more strategic warheads, as well as 1,912 nonstrategic warheads" are held in reserve.

What threat do the weapons pose to Ukraine?

Russia's intercontinental ballistic missiles (ICBMs) are capable of reaching and devastating major global cities such as London and Washington. ICBMs have a peak speed of around 10 minutes after launch, therefore one fired from Russia could reach the United Kingdom in less than 20 minutes.

"President Putin has increased the stakes - he's started to infer nuclear weapons on a global scale," said defence expert General Sir Richard Barrons. "This refers to equipment such as an intercontinental ballistic missile, that reaches from Russia to the United States and of course, into Europe." "The front-facing warhead has a yield of between 300 and 800 kilotonnes" (of TNT equivalent).

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