The Prime Minister will tell members of her top team they should keep quiet about the content of meetings and focus on getting on with the job of governing, Mrs May’s spokesman said.
The bid to instil discipline comes after alleged comments by Chancellor Philip Hammond at a Cabinet meeting on Tuesday appeared on the front pages of two different newspapers.
Mr Hammond is said to have told the meeting that public sector workers are “overpaid” and “even a woman can drive a train”.
The leaks culminated in an unnamed minister telling one newspaper the Chancellor “is trying to “f*** up” Brexit.
The extraordinary disclosures have exposed the deep divisions at the heart of Government as Britain attempts to negotiate Brexit and Mrs May battles to keep her job in the wake of her miscalculated General Election gamble.
Mr Hammond has seemed to suggest Cabinet colleagues are briefing against him because they don’t like his position on leaving the EU.
The Chancellor’s insistence that the focus in Brexit negotiations must be on “protecting our economy” has irked some within his party.
The row is being perceived as another example of the PM’s weakness in the wake of June’s election, which saw her lose her Commons majority.
But Mrs May’s spokesman made clear she intends to lay down the law by telling ministers to focus on their departmental responsibilities.
“She will be reminding them of their responsibilities and making the point that ministers across Government need to be focused on getting on with delivering for the British public,” he said.
“I’m not going to get into speculation of who said what where and when.
“I’m simply saying that Cabinet must be able to hold its discussions on Government policy in private, and the PM will remind her colleagues of that at tomorrow’s meeting.”
Asked whether the PM rejected the claim that Mr Hammond was trying to sabotage Brexit, the spokesman said: “I’m not getting into anonymous quotes.
“What I would say is that the Government is all working together to deliver Brexit, which delivers on the will of the British people.”
The spokesman said he was not aware of an inquiry into the source of the Cabinet leak.
Amid infighting back home, Brexit Secretary David Davis headed to Brussels for the second round of negotiations with the EU’s chief negotiator Michel Barnier.
Mr Davis said the talks would cover the “substance” of leaving the EU, while Mr Barnier said they would “delve into the heart of the matter”.