See the trailer for true-life drama The Walk-In, starring Stephen Graham

The ITV series is set to air in October.

Video transcript

[MUSIC PLAYING]

Look at this fellow here. He was one of the leading lights in the far right in this country.

I've written a piece about National Action being the biggest threat from the far right.

That's me in that photograph 20 years ago.

We need to be stronger. Ready for the war that's coming.

We've got to get someone inside this group.

I did some bad things.

You're not that person anymore.

Them tickets go feed everyone around. You ought to mix with people more.

If they are planning something, we won't know about it until it's too late.

I need that walk in.

Why do you want to join National Action?

[INAUDIBLE]

First sign of any trouble you call me.

We need his name.

He's trying to [INAUDIBLE] push.

You're out of your depth.

Are we going to have to move again?

He's got kids, doesn't he? Find him.

What's going on, Robby?

Nothing is going on.

This is the murder of an MP.

Exactly what National Action have been waiting for.

"The Walk In," this October on ITV and ITV hub.