If Germany's audacious plan to invade Britain - Operation Sea Lion - had succeeded, what exactly would the country's last line of defence have looked like?

Well much like the French Resistance, who were backed by the UK's very own Special Operations Executive (SOE), Britain had prepared its very own network of brave civilian saboteurs, spies, and assassins - many of whom went to their grave without revealing a word of what they'd been tasked to do.

In this episode James is joined by historian & author Andrew Chatterton, who helps us understand exactly what a British Resistance movement would have looked like.

Mark's new book Britain’s Secret Defences: Civilian saboteurs, spies and assassins during the Second World War is available here.

For more Warfare content, subscribe to our Warfare Wednesday newsletter here.

If you'd like to learn even more, we have hundreds of history documentaries, ad free podcasts and audiobooks at History Hit - enter promo code WARFARE for two weeks free + 50% off your first three months' subscription. To download, go to Android or Apple store.