Therese Coffey was skewered on Sky News after she tried to downplay the significance of the Suella Braverman speeding row.
The home secretary has been accused of breaking the ministerial code after reportedly asking Home Office aides to help her dodge a fine.
After failing to arrange a private awareness course, Braverman eventually agreed to accept three penalty points and pay a fine over the incident, which happened last summer when she was attorney general.
At a press conference in Japan this morning, Rishi Sunak pointedly refused to offer the home secretary his full backing over the controversy.
Appearing on Sky News shortly afterwards, environment secretary Coffey told presenter Sophy Ridge that she was unaware of the story until shortly before going on air.
She said: “I’ve only read the newspapers like your good self, I haven’t got any extra information. I’m not aware of any further details on that.
“It’s perfectly normal nowadays, if people are found speeding, to be offered points or to go on a course of some kind.”
Ridge said: “Do you get why viewers might find it a bit frustrating that ministers can come on and say ‘I don’t know the details, I’ve got nothing to say on this because I just don’t know’ when it’s obvious that we’re going to ask questions about this?”
Coffey said she had only read the story 20 minutes before the interview and was not “in the business of phoning people at 20 past seven in the morning” to get more details.
Ridge then asked the minister: “Do you just not think it’s a big deal then, because you seem to be quite relaxed about it.
“It is a big deal, isn’t it? She’s asking the taxpayer-funded civil service to get involved in her personal affairs?”
Coffey replied: “What I’ve said is I’ve scanned the newspapers myself this morning before coming on the show. I’m not in the business of phoning people at 20 past seven in the morning to try to get chapter and verse ...”
But Ridge said: “What, even if they might have broken the ministerial code?”
The minister said the presenter was “making all sorts of allegations” and that she did not have the full details of the story.
She added: “What is clear is Suella has three points on her licence and is getting on with the job of tackling particularly illegal migration, but also the wider security elements of our country.”
A stunned Ridge then said: “I’m not really sure what to say, to be honest.”
Both Labour and the Lib Dems have demanded that Sir Laurie Magnus, Rishi Sunak’s ethics adviser, launch an investigation into whether Braverman has broken the ministerial code.
At his press conference this morning, the PM said: “I don’t know the full details about what has happened, nor have I spoken to the home secretary. I think you can see first hand what I’ve been doing over the last day or so.
“But I understand that she’s expressed regret for speeding, accepted the penalty and paid the fine.”
A spokesman for the home secretary said: “Ms Braverman accepts that she was speeding last summer and regrets doing so. She took the three points and paid the fine last year.”