Theresa May is to put "some meat on the bones" of what she wants from Brexit as Tory divisions on withdrawal again broke into the open.
International Development Secretary Penny Mordaunt said a series of major speeches planned by the Prime Minister and Cabinet heavyweights would set out a Brexit "vision" over the next three weeks
She told BBC1's The Andrew Marr Show: "What the public want is, they want the vision and they want some meat on the bones."
The upbeat message came as leading Tory rebel Anna Soubry delivered a warning to the PM.
Asked if she believed there is a majority in the House of Commons to defeat "the kind of Brexit the Prime Minister wants", Ms Soubry told The Andrew Marr Show: "If she's not careful, yes."
Pressed on whether she thought Brexit will definitely happen, Ms Soubry, who was making a joint TV appearance with pro-Europe Labour MP Chuka Umunna, said: "Will it definitely happen? I genuinely don't know what is going to happen."
Parliament is not a bystander in the Brexit process, and will not give government a blank cheque. We will get a meaningful vote, and MPs across parties are willing to vote against the government if the deal is against the interests of our constituents. pic.twitter.com/qZXeEqtjsg
-- Chuka Umunna (@ChukaUmunna) February 11, 2018
Ms Mordaunt insisted she believed a transition period was "a given" despite claims to the contrary by EU chief negotiator Michel Barnier.
She said: "What I would say to the public is that, actually, the other nations involved in this are very pragmatic and have not been impressed with some of the language that the (European) Commission has used."
Asked if it was a Government red line to not have to grant full rights to EU migrants who come to Britain during a transition period, Ms Mordaunt said: "It is what we are setting out in our position. Again, all of this is a negotiation.
"Ultimately, it will be the negotiation, the phrase that is trotted out - nothing is decided until everything is decided."
The Prime Minister is set to make two key note addresses in the coming weeks, and arch Brexiteers Boris Johnson, David Davis and Liam Fox will also set out their agendas.
However, Chancellor Philip Hammond is not slated to take part in what Downing Street sources dubbed a drive to set out Britain's road map to Brexit.
The wave of speeches comes as a Tory party donor warned the Conservative Party would be "decimated" at an election unless Theresa May could "take the bull by the horns" and show strong leadership.
The public relations blitz is being seen as an attempt to try and set the tone in the run-up to another round of tough negotiations with Brussels over a transition deal.
In the first of the speeches on Wednesday, Foreign Secretary Mr Johnson will call for national unity over withdrawal.
This will be followed on Saturday by Prime Minister Theresa May detailing the "security partnership" the UK wants to maintain with the EU.
Brexit Secretary Mr Davis and International Trade Secretary Dr Fox will also set out their agendas, along with Cabinet Office Minister David Lidington, who backed Remain in the referendum.
Mrs May will then round off the process in an address setting out how she sees the overall relationship between Britain and Brussels after withdrawal.
After a rocky few weeks for the Government, in which Cabinet tensions over Brexit broke to the surface, Tory party donor Sir John Hall warned that the PM needed to "stand up" and "convince everybody that she can be the leader who can stay".
He told the Observer: "She's got to take the bull by the horns and say, 'this is the road we are going. Do your damnedest - if you want to vote me out, vote me out'.
"But we have to appear stronger."
He added: "If we had an election, I reckon we'd be decimated. To me as a donor, the Conservative party has to look at itself in terms of where we're going.
"She has got to stay to such time that someone else comes forward. A new leader has to emerge - or she has to come through very strongly."
As well as the speeches, members of the Cabinet's Brexit sub-committee will attend an "away day" summit at the Prime Minister's country residence Chequers.
Mr Barnier pointedly complained last week that there were still "problems" in Brussels "understanding the position of the British Government".