What's behind Putin's mobilisation?

<div>Vladimir Putin warned the West that, if pushed, Russia would use a nuclear weapon. How seriously should we take his threat? And reports emerged overnight that Liz Truss will cut stamp duty to increase demand for housing. But will that help more people get onto the housing ladder? <br> <br> Katy Balls speaks to James Forsyth and Isabel Hardman.<br> <br> Produced by Max Jeffery.</div>