Liz Truss accuses Vladimir Putin of sabre rattling and warns UK won't back down

Today, Liz Truss will deliver a speech to the UN in which the centrepiece will be her ongoing tough language about Vladimir Putin.

She will accuse the Russian president of doubling down this morning with his threat to the West, adding: "He is desperately trying to claim the mantle of democracy for a regime without human rights or freedoms. And he is making yet more bogus claims and sabre-rattling threats."

Accusing the Russians of using rape as an "instrument of war" and using "barbarous weapons" to kill and main people, she will add that his threats will not work.

"The international alliance is strong - Ukraine is strong."

On the question of Ukraine, Truss will be able to build the strongest bonds with the US and many European countries.

Although Joe Biden maybe frustrated about Britain's position on the Northern Ireland protocol, he knows that the countries can stand together on their position on Ukraine; and while her relationship with Emmanuel Macron maybe bruised by her "jury's out" following a "friend or foe" question, she knows they agree on Russia.

But there is a bigger and harder question about a true international alliance on Ukraine, that is visible at the UN general assembly.

On day one, the strength of position on Ukraine from European countries, and Russia's neighbours was clear, but experts point to a more "muted" response from many developing countries.

Many of those countries, including a number across Africa, have important alliances with China - who have notably remained neutral on Russia and even criticised NATO as being provocative.

But also while they have all condemned Russia for its invasion of Ukraine, they are more sceptical of the western response and some blame the west's retaliatory economic sanctions for the pain they've suffered as a result of the food insecurity triggered by the war.

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It is worth noting that British diplomats are very clear that only Russia are responsible for the rising food prices caused by grain getting stuck in Ukraine but developing countries have been lobbied to believe the opposite.

So could their quiet response change now that Putin has made such a shocking intervention, with a speech including a nuclear threat?

One expert told me they might. Richard Gowan, UN director of Crisis Group, told me that a lot of non-western leaders have been "hedging their bets over Ukraine at the UN" - calling for negotiations and avoiding criticising Russia.

"I think that Putin's referendums gambit and nuclear threats may change the dynamic at the UN in the next few days." He argued that the basic principle of countries' territorial integrity was a red line for those countries - as they see comparisons with Palestine and Western Sahara.

The threat, therefore of referenda that US Secretary of State Anthony Blinken called "sham" followed by annexation, would therefore be highly provocative to those countries.

"The US and its allies will be urging African and Asian countries to see what Russia is doing as an act of colonials military and appealing to their anti-imperial instincts," added Gowan.

That is why he believes that Western diplomats, including in Britain, will be more confident now about rallying a big coalition of countries to condemn Moscow.

He said Putin didn't care about the UN but had now "undercut Russia's position at the general assembly" making it harder for non-Western leaders to remain "passive".

That is what Truss and her closest allies will be hoping for.