Alistair Jackson is a highly experienced investigative journalist. For years he's worked as a producer and a reporter for BBC's flagship investigative show, Panorama.

With years of reporting under his belt, Alistair has a well-trained nose for his story.

And he's all too aware that inspiration for an investigation can come in many forms.

Some people come to you with information and then others can be totally self-driven by the producer or journalist who has an idea that matures into something.

So it can be a combination of anything.

But a few years ago, something happened that would set Alistair off on an investigation

that was like nothing he'd done before.

What happened was a worse thing imaginable.

I'm Mavnegan.

This is the tip-off.

It was November, and Alice was enjoying a family holiday in Dorset, with his wife and children.

When out of the blue, he got a phone call from his brother.

One of those terrible phone calls that you always fear,

as you have elderly parents,

that my mum was pretty ill in hospital in the Midlands where I'm from.

The first call was that she's had a funny turn.

She's been taken into hospital,

but you don't need to worry too much.

And then a few hours later I got a much more serious phone call,

which we made it pretty clear that I needed to get in the car. Trying to fight the feeling of rising dread,

Alistair started the long drive up to the Midlands. It was a horrible November evening and it was as you can imagine felt a very long drive going up there. Arriving at Queen's Hospital in Burton upon Trent,

Alistair was told that Margaret, his 78-year-old mother,

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