For him, the problem is not only performance, it's structure.

We all of us have to drink water, use water, use the toilet, and we can't go to another company and say we're gonna go to another one.

We can't do that.

They are monopoly companies.

They're exploiting us.

Anger erupted in many corners, including Ash Smith from WASP.

There's been no competition.

The competition has all been about how much money can we extract.

How much money can we pay ourselves? Those ludicrous bonuses that the water industry says you have to pay to get the right standard of chief executive.

And they've had the right standard of chief executive, apparently, for Thames Water for the last however many years.

And they've driven the company off a cliff.

And they're now using that cliff hanging situation to blackmail the government into making customers pay even more for it.

He gives the company a modicum of credit for its map.

They were the first company to put out the sewage map.

They're going to like me saying this, I know that.

They put out the sewage map and they did it very honestly with honest colours.

Green, amber and red.

Whereas with some of the other water companies, you're getting like a colour chart of vague shades of purple meaning different things.

You have to guess that by... by kind of spending half a day with grid references.

Today, public perception of the River Thames is at a fresh low, fuelled in part by Dirty Business, the Channel 4 docudrama which follows the investigations of Peter Hammond and Ash Smith.

Illegal pollution is profitable.

Thames Water is not an exception in adopting that.

They've all done it.

All the water companies act like this.

They are dumping untreated sewage for months on end.

Months.

Ash believes that the River Thames itself gets off relatively lightly.

He gives the company a modicum of credit for its map.

They were the first company to put out the sewage map.

They're going to like me saying this, I know that.

They put out the sewage map and they did it very honestly with honest colours.

Green, amber and red.

Whereas with some of the other water companies, you're getting like a colour chart of vague shades of purple meaning different things.

You have to guess that by... by kind of spending half a day with grid references.

Today, public perception of the River Thames is at a fresh low, fuelled in part by Dirty Business, the Channel 4 docudrama which follows the investigations of Peter Hammond and Ash Smith.

Illegal pollution is profitable.

Thames Water is not an exception in adopting that.

They've all done it.

All the water companies act like this.

They are dumping untreated sewage for months on end.

Months.

Ash believes that the River Thames itself gets off relatively lightly.

I'm Kate Lamble, and from Understand from BBC Radio 4, this is Rinsed.

Last time I was here, there was a tampon and there was a condom.

Uncovered by ordinary folk taking on powerful people.

And they told me, "There's nothing wrong with the River Windrush.

Basically, go away and stop troubling us."

Am I proud of what we've achieved? Yes.

Um, I agree.

We don't do chest-beating like gorillas, but we appreciate being appreciated.

We're proud of what we've done.

We've always been honest.

We've always told the truth.

You know, we've never exaggerated.

Their dream now is to be released from that obligation, to return to the retirements they planned, enjoying the river rather than fighting for it.

Through Westminster and across newsrooms, striking a chord with people around the country.

The moment for me is when I'm travelling down in the car and it's a dark, stormy evening, I think.

And I'm listening to radio and it's radio for comedy, The Now Show.

You remember Moses, the guy who partied the Red Sea and then filled the gap with sewage.

And I thought, wow, because if you can make that joke to a national public audience and expect enough of them to know about it to be able to know why that's funny, that means we've got it.

It probably would've been if it wasn't for his neighbor, Peter Hammond.

I didn't realize that my neighbor was a talented mathematician, data analyst, uh, with expertise in being able to deal with millions of lines of data that for me are like a complete and utter mystery.

They're not for him.

I was amazed that he had the nerve to do it and that they didn't stop him.

I thought it was a perfectly normal thing to do.

[laughs] You know, he thinks it's perfectly normal to take a, a billion numbers and turn them into a picture.

I think it's perfectly normal to do what I think is right in the public interest, even if it might, might be a bit of an uncomfortable moment.