Former health secretary Matt Hancock tried to bypass the education secretary to have schools closed in December 2020, the Daily Telegraph has reported.
In leaked WhatsApp messages, Mr Hancock said Sir Gavin Williamson was battling "tooth and nail" to keep schools in England open, a move he disagreed with.
Other messages show disparaging remarks about teachers' unions and belittling comments towards Sir Gavin.
It is the latest revelation to come from the leaked text messages.
The Telegraph was passed more than 100,000 messages, sent between ministers and officials during the pandemic, by journalist Isabel Oakeshott.
A vocal critic of lockdowns, Ms Oakeshott obtained them while helping Mr Hancock write his book, Pandemic Diaries. The journalist has said she broke a non-disclosure agreement to release the messages because they are "in the public interest".
The BBC has not seen or independently verified the WhatsApp messages nor the context in which they were sent.
A spokesperson for Mr Hancock said the leaks offer "partial accounts, obviously spun with an agenda".
One exchange on 28 December 2020 appears to show Mr Hancock messaging an aide during a video meeting with then-Prime Minister Boris Johnson to discuss rising Covid cases.
At that point, the plan was for all primary schools to return as normal in January, and for the opening of secondary schools to be delayed by two weeks to allow time for mass testing to be set up.
Mr Hancock, who wanted to keep school closed, described Sir Gavin as battling "tooth and nail" to keep schools open and "going absolutely gangbusters" over the issue.
"He's freaking out. You can tell he isn't being wholly rational... just by his body language," Mr Hancock's aide, Emma Dean, wrote.
"I'm having to turn the volume down," Mr Hancock responded.
Later, having apparently failed to persuade the prime minister that schools should stay shut, Mr Hancock wrote: "The next U-turn is born."
He then adds: "I want to find a way, Gavin having won the day, of actually preventing a policy car crash when the kids spread the disease in January. And for that we must now fight a rear-guard action."
Mr Hancock then contacted Dan Rosenfield, Mr Johnson's chief of staff, to discuss how to "avoid the car crash we have just set up for January".
In an exchange on 1 January, as Covid cases continued to rise, Mr Hancock described Sir Gavin as having had to eat "a lot of humble pie".
On 3 January, the prime minister repeatedly insisted that "schools are safe" on BBC One's Andrew Marr Show.
But the next day, hours after pupils returned to the classrooms, he announced the closure of all schools and colleges, as they "may act as vectors for transmission".
Writing for the Telegraph, Sir Gavin said he felt the closure "wasn't done for the right reasons" and he considered resigning in protest over the decision. He remained as education secretary until September that year, when Mr Johnson reshuffled the cabinet.
Unions 'just hate work'
Messages between Mr Hancock and Sir Gavin in May 2020 also show them discussing a shortage of personal protective equipment (PPE) for schools.
Sir Gavin said he wanted to make sure the PPE was provided so that schools "can't use [the shortfall] as a reason not to open" and that some would want to use it as "an excuse to avoid having to teach".
That October, Sir Gavin announced that A-level exams would be delayed by several weeks, a shorter period than some teaching unions had called for.
"Cracking announcement today," wrote Mr Hancock to Sir Gavin. "What a bunch of absolute arses the teaching unions are."
Sir Gavin replied: "I know they really really do just hate work."
Mr Hancock responded with some emojis of a person laughing and another of a dart hitting a bullseye.
Geoff Barton, general secretary of teaching union, the Association of School and College Leaders, said the reported comments made by Sir Gavin were "contemptible".
He told BBC Breakfast: "It's contemptible because we have to remind ourselves that this was an age of extraordinary anxiety. We hadn't got vaccines."
Mr Barton said there was a "very snarky debate" going on about whether face coverings should or shouldn't be worn.
"The very people who then brought those young people back into school are being described in those snide terms by the former education secretary," he said.
He added that, as someone who wants the "brightest and best" young people to become politicians "that is less likely this morning because of that sneering denigration of the teaching profession."
Writing on Twitter following the publication of the texts, Sir Gavin said he wanted to "clarify that these messages were about some unions and not teachers".
"I have the utmost respect for teachers who work tirelessly to support students," he wrote. "During the pandemic, teachers went above and beyond during very challenging times."
BBC
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