I'm Rory Stewart and I grew up wanting to be a hero and I'm still fascinated by the ideas of heroism.

In my new series, I'm taking in the long sweep of history from Achilles to Zelensky and asking, what is a hero?

Simply doing your job, being a decent human being.

A true hero is someone who just kind of shines by

their own light and that light is to be recognised by others. The long history of heroism

with me, Rory Stewart. Listen on BBC Sounds. BBC Sounds, music, radio, podcasts. Hello, I'm Sheila Dillon.

It's wildness, fresh waters and invasive shellfish, millions of them.

Shellfish that are also delicious.

So why shouldn't we just eat them?

Eat them to extinction, as my colleague Dan Saladino might say.

That's the issue in this edition of the food program.

No one will be setting off fireworks or hiring jazz bands,

but next year marks 50 years since a certain crustacean

first invaded UK waters, the American signal crayfish.

Since then, there's been no stopping them,

decimating our fish and their native white-clad cousins,

as well as undermining riverbanks and exacerbating flooding.

You see lots of little three-inch holes that everybody sort of thinks, oh, they're rat holes.

But they're not, they're crayfish burrows, and they go back about two to three feet,

and then that collapses and goes into the river.

We'll hear more from Andrew Leach by the River Kennet later.

Right now I'm faced by a lot, really a lot of them,

...