The two big unknowns left up in the air after Starmer's 'coalition of the willing' Ukraine summit

There was one clear, united message from today's virtual meeting of leaders - that they rejected Vladimir Putin's "yes, but" approach to a ceasefire.

The "coalition of the willing" - the 27 leaders, plus NATO and the EU led by Sir Keir Starmer and Emmanuel Macron - want the Russian president to mirror Ukraine's pledge for a 30-day pause in fighting, in order to hammer out a sustainable peace deal.

Sir Keir made that very clear, and suggested the attendees at the meeting were behind this approach.

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The prime minister said: "Volodymyr [Zelenskyy] has committed to a 30-day unconditional ceasefire, but Mr Putin is trying to delay, saying there must be a painstaking study before a ceasefire can take place.

"Well, the world needs action, not a study, not empty words and conditions. So my message is very clear. Sooner or later, Putin will have to come to the table."

There are two reasons for this challenge - an immediate end to fighting is a goal in itself, but many of those in today's call, including Sir Keir, do not trust Mr Putin to uphold promises on peace and are trying to convince US President Donald Trump to be more clear-eyed about the Russian approach.

Challenging the Russian leader to follow the US request for a ceasefire and watching him refuse is designed to send a message to the White House as well as the Kremlin.

There were, however, bigger unknowns left hanging.

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One of which was the clear signal from Sir Keir that he is still relying on a US security guarantee in order to bring on board a "coalition of the willing" who might be able to provide troops to Ukraine.

There are, however, many that don't think that that US security guarantee is coming in any substantial way, based on the noises coming out of the US.

That is a big problem for the PM, as government sources tell me that the scope and the remit of any potential peacekeeping force is determined by what protection the US might be able to provide.

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The second issue that is being sidestepped by Sir Keir is what any peace keeping might be able to do in practice.

UK troops, like those of any NATO country, cannot engage directly with Russia in combat for fear of triggering a much bigger conflagration.

So if not that, then what is their purpose - a question repeatedly asked by experts like the former national security adviser Lord Ricketts.

I put exactly this to the PM, but did not get an answer. He suggested that we were a long way away from getting an an answer, even though military chiefs also appear to be meeting to "operationalise" plans on Thursday.

How can they operationalise a plan that does not, and currently cannot, have a remit?

Today Sir Keir heralded the participation of Canada, Australia and New Zealand on the call, as part of the effort.

But if the remit of the coalition of the willing isn't clear, how can it truly be effective?

(c) Sky News 2025: The two big unknowns left up in the air after Starmer's 'coalition of the willing' Ukraine summ