Before you listen to this BBC podcast, I'd like to quickly tell you about some others.

My name's Andy Martin and I'm the editor of a team of podcast producers at the BBC in Northern Ireland.

It's a job I really love because we get to tell the stories that really matter to people here,

but which also resonate and apply to listeners around the world.

And because the team is such a diverse range of skills and strengths,

we have trained journalists, people who love digging through archives,

we've got drama and even comedy experts.

We really can do those stories justice.

So if you like this podcast, head to BBC Sounds

where you'll find plenty more fascinating stories from all around the UK.

I whistle and I whistle and my memory goes back.

I'm alone in solitary confinement in a prison near the center of Cape Town,

feeling desperate, determined to survive the solitary confinement.

The security police have locked me up and they want information from me and it's about the struggle

against apartheid. It's 1963 and I'm trying to be brave and I march in my tiny little

cell and I sing and I whistle and I whistle and I sing. I can't see anything. I can't see

outside but I hear din, shouting, screaming,

and I'm trying through music to keep myself with a sense of sanity and personality.

And I'm whistling, and I'm trying to communicate. Is anybody else in the prison who's hearing me, please, please respond?

And I sing and I whistle A&C songs and Kosi Secularly Africa, and there's no response.

And the people's flag is deepest red, and whistle and there's no response and then I go

and I think I hear whistling from deep in the prison.

...