A week after Ukraine invaded the Kursk region of western Russia - when around 1,000 troops surprised analysts by storming across the border - Russia’s President Vladimir Putin vowed to “kick the enemy out of our territory”.     But has the success of Ukraine’s incursion threatened his grip on power?     On the Sky News Daily, Niall Paterson is joined by our security and defence analyst Michael Clarke to explore the reasoning behind the timing of the invasion, and Peter Dickinson, editor of the UkraineAlert blog for the Atlantic Council based in Kyiv, explains how the invasion has exposed the weakness of Putin’s ‘red lines’.       Producer: Rosie Gillott Podcast promotions producer: David Chipakupaku Editor: Philly Beaumont