Therese Coffey was left squirming after being asked on live television whether she would go swimming in sewage-infested water.
The environment secretary was put on the spot by the BBC’s Laura Kuenssberg amid mounting public anger over the problem.
Coffey has faced calls to resign after it emerged water companies pumped sewage into Britain’s waterways over 300,000 times last year.
On the Sunday with Laura Kuenssberg show this morning, the minister was shown video of sewage spilling into the sea.
The presenter said to her: “We can look at some of the footage of sewage being spilled out into the sea - I hope we’re not putting anybody off their breakfast.
“Would you go for a swim in that?”
Coffey replied: “It’s a combination of what was happening, is coming out of the storm overflows. What is going through is when we have a particular rainfall, that’s when they’re supposed to be triggered.
“The water companies are already under a criminal investigation about what’s been happening with storm overflows.
“But frankly we would not even know about this if it wasn’t for a Conservative government had started to insist on the monitoring and the publication of that data.”
But Kuenssberg replied: “My question for viewers in England is would you go for a swim in that kind of water? What advice would you have for people? The weather’s warming up - would you let children go swimming in water like that?”
Coffey insisted that water quality in the UK had actually increased under the Tories.
She said: “We have over 400 designated bathing sites across the country.
“The good news is that since 2010 we’ve seen the quality of that bathing water significantly increase.”
After Kuenssberg told her that, according to the European Environment Agency, the UK’s waters were “the worst in Europe”, the minister hit back: That’s just not true.”
She said: “The point is that we now have 92.9% of our bathing waters rated good or excellent last summer - that’s up from 70% in 2010.”
Coffey was also asked about people’s bills having to go up in order to pay for the clean-up operation at a time when water bosses are raking in millions in salaries and bonuses.
She said: “Consumers aren’t going to be paying for the illegal discharges, the fines and penalties that have already been levied.
“But there has to be ongoing investment in these things.”