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It might not sound much, but a few small words can make a big difference.

In the last few minutes, the president of the European Council, Donald Tusk, has used the prime minister's language about the Salisbury attack, accepting and agreeing with the British verdict that there is no other "plausible" explanation for what happened.

That is a small, but significantly different, tone to a statement a few days ago.

EU ministers would only say: "The European Union takes extremely seriously the UK government's assessment that it is highly likely that the Russian Federation is responsible."

The sentiment then was, okay, it might have been them - but you haven't convinced us yet.

Now, although plenty of EU leaders - as well as Labour at home - have made clear they would like to see more evidence, today the council as a group has been ready to give firmer backing to Theresa May's claims.

It doesn't, however, seem likely that tonight or tomorrow the prime minister will have persuaded any other leader to take precisely the same kind of actions she has at home - although the possibility of expelling diplomats was not completely thrown out of hand by some of them.

Different EU states have very different relationships with Russia.

Greek leader Prokopis Pavlopoulos even had a chat with President Vladimir Putin on the phone this morning before the summit.

But for those in No 10 who want to see this moment to crank up a new tougher line internationally towards the Kremlin, the tweak of a few crucial words is a start.