World leaders scramble to defuse ‘monstrous’ new crisis over Russia’s downed jet: Putin ratchets the tension by dispatching warship to Mediterranean as Moscow expert warns war is ‘likely’

• Russia warns of ‘serious consequences’ after Nato country downs Russian military jet for first time since 1953
• Two pilots were reportedly shot dead by Syrian rebels as they parachuted from burning Sukhoi Su-24 warplane
• Third Russian said to have died when rescue helicopter was hit with anti-tank missile by another rebel group
• Russia denied plane had been in Turkish airspace but Nato secretary-general says assessment showed it had
• A warship has been deployed to the Mediterranean Sea to destroy potential threats to Russian forces in Syria
• Britain has declared military back-up is on standby to support Turkey in any revenge attack by Putin’s forces

A ‘monstrous’ new crisis has begun after Turkey shot down a Russian military plane, sparking fears of a war.

Vladimir Putin  has accused the Turks of a ‘stab in the back’, branding them ‘accomplices of terrorists’.