Rumoured to run to 120 miles, Russia is digging a vast trench stretching the full length of Ukraine’s eastern flank. An enormous feat of engineering, but does it mean they’re digging in or desperate? The BBC’s security correspondent, Frank Gardner, tells us that this line of defence, like the Maginot Line before it, is no guarantee against a Ukrainian advance.

We also hear about the alleged use of cluster bombs. Human Rights Watch says it’s seen the tell-tale fragmentary patterns left by the explosions and spoken to people who have lost limbs.

And Owen Matthews, author of 'Overreach', explains why President Putin invaded Ukraine, and the reasons it isn't going well for him.

Plus listeners share Ukrainian songs and artwork they’ve discovered since the war began.

Today’s episode is presented by Victoria Derbyshire and Vitaly Shevchenko.