Why is a no-fly zone a no go?

<div>During a press conference in Poland today, Prime Minister Boris Johnson was confronted by Ukrainian journalist and campaigner Daria Kaleniuk, who took issue with the excuse for not imposing a no-fly zone because it may start World War Three, saying it had already begun. <br> <br> While it is completely understandable that on the streets of Ukrainian cities that is how it must feel, the UK and the West are committed to not involving themselves with direct military action against Russia. Though the sanctions that have been imposed on Putin's regime are unprecedented, can they work quickly enough to pause the conflict before things get even bloodier?<br> <br> Katy Balls talks to Isabel Hardman and James Forsyth about how the Prime Minister has been handling this situation so far.</div>