Putin may unleash chemical weapons in just weeks as he feels 'cornered' and 'rattled' by Ukraine invasion into Russia

"Putin is absolutely rattled,” he said, speaking to The Sun.

"He could have lost up to 700,000 soldiers already.

"Now, with Ukraine hitting back using US ATACMS and British Storm Shadow missiles, he knows his forces in Kursk are sitting ducks.”

As the Ukrainian capital launched its first US-made ATACMS missiles, a Russian military depot was hit in Bryansk - on the 1,000th day of the Russian invasion.

The attack was promptly followed by Ukraine launching UK-made Storm Shadow missiles two days later.

The move infuriated Moscow, and led to Russia firing off an intercontinental ballistic missile for the first time throughout the war.

LATEST DEVELOPMENTS:

• British Army fires next-gen weapon for first time in one of Nato's largest EVER artillery exercises
• Europe fumes as Russia accused of 'systematically attacking' Baltic Sea fibre-optic cables
• Putin targets Ukraine with 'massive' intercontinental ballistic missile

On the same day, the Kremlin approved changes to the nation’s nuclear doctrine, lowering the threshold to consider a nuclear strike.

However, the ex-commander has claimed that Putin’s moves are nothing but “bluff and bluster”, insisting that Nato’s intelligence and weapons systems would prevent Putin from carrying out a successful nuclear attack.

Still, de Bretton-Gordon has said that Russians are increasingly using a chemical called chloropicrin. He said: "If Putin substituted that chloropicrin with the Novichok that he used in Salisbury, then, thousands of people could be killed.”

Additionally, he suggested that whoever takes ahold of the strategic region of Kursk might determine the war’s final outcome.

He said: “Whoever holds Kursk come Christmas time will be on the front foot for the expected Trump negotiations and ceasefire at the end of January next year."

Encouraging Nato to supply Ukraine with resources, he added: “Hopefully these last four weeks are really beneficial to Ukraine.

"And hopefully it’s better late than never rather than too late.”

Over the weekend, president Biden gave authorised permission for Ukraine to fire the American-made missiles inside Russia.

Meanwhile, the UK’s Storm Shadow rockets are able to dodge air defences, costing around £800,000 and capable of travelling at speeds up to 600 miles per hour.