Theresa May will brief senior ministers on her plans for Brexit before a major speech aimed at helping to break the deadlock in the negotiations with Brussels.
The Prime Minister will chair a special Cabinet meeting after returning from New York, where she used the gathering of world leaders at the United Nations General Assembly to hold talks with key EU counterparts.
The Cabinet meeting will be an opportunity for Mrs May to attempt to unite her team behind her strategy after Foreign Secretary Boris Johnson published his personal Brexit manifesto, triggering a round of infighting within the senior ministerial ranks.
In a move which will fuel speculation that the Prime Minister could try to go over the heads of Brussels officials, Mrs May said the final decision on the Brexit deal would be taken by the leaders of the 27 other European Union members.
Formal talks on the withdrawal process in Brussels are being led on the EU side by Michel Barnier, who was appointed by the European Commission to carry out a negotiating mandate agreed by leaders of the 27 remaining member states in the European Council. He has fiercely insisted that formal discussions must come through him, as the representative of all 27.
But Mrs May highlighted the role that would be played by the individual leaders - some of whom she held talks with while at the UN.
Before the New York talks, Mrs May said: "The negotiations are structured within the EU so of course the Council has delegated with a mandate to the commission, and the commission has appointed Michel Barnier.
"But the decision will always be one that will be taken by the leaders."
In the margins of the New York gathering, Mrs May met French president Emmanuel Macron, Italian PM Paolo Gentiloni and the Netherlands' Mark Rutte, although Downing Street did not say whether Brexit was on the agenda for the talks.
The Prime Minister will deliver a speech in Florence, Italy, on Friday which will be keenly scrutinised in Westminster and Brussels before a further round of negotiations starting next week in Brussels. The speech has also taken on increased significance in terms of party management following Mr Johnson's intervention.
The Foreign Secretary was forced to deny he was planning to resign, while Mrs May faced calls for her to sack him from her Cabinet after he published a 4,000 Brexit blueprint.
In a sign of the divisions at the top of the party, Mrs May's former chief of staff Nick Timothy used a column in the Daily Telegraph to accuse Philip Hammond's Treasury of failing to promote the positives of Brexit. The Chancellor's department had failed to emphasise the "opportunities of Brexit" and Mr Timothy accused Mr Hammond of being on "manoeuvres".
Calling for unity he said: "Boris Johnson and Philip Hammond - who has also been on Brexit manoeuvres this summer - must understand that the surest route to a bad deal, or no deal at all, is to go on behaving as they are."