He said tabling the confidence motion – meaning Tory MPs would lose the whip if they voted against it – would “risk open rebellion”.
Another former minister said: “It is exactly what many of us warned would happen. It is a disaster and completely self-inflicted. It feels like Black Monday 1992 all over again.
“There is no way it will pass the Parliament. The Prime Minister and Chancellor should do a U-turn and change policy on tax cuts and energy bailouts with a much more targeted package and hope the public don’t care about the visuals, only their bills. Otherwise, the Bank of England will have to keep raising interest rates and cause a massive housing crash.”
A senior campaigner pointed out that MPs would never vote against a full Budget, but said that because this was a mini-Budget, there would be “all sorts of jiggers”. The MP, who supported Mr Sunak in the leadership contest, pointed to the “fundamental political weakness” of Ms Truss, whose support is “really very shallow”.
Another said the scale of anger was “massive”, adding: “People are really upset – this is a self-inflicted crisis. We must be the party of financial responsibility or we are nothing. It is very likely that people will vote against the 45p tax rate – there are a lot of people who have no reason to support the government.”
A Treasury spokesman said: “Last week the Chancellor unveiled the first stage of the government’s Growth Plan, with more supply-side reforms to come in the coming weeks – including announcements about changes to the planning system, business regulations, childcare , migration , agricultural productivity and digital infrastructure.
“And the Chancellor has commissioned the OBR to produce an economic and fiscal forecast to be published on 23 November. At the same time, he will present the government’s Medium-Term Fiscal Plan, which will be based on a commitment to reduce debt as a share of GDP in the medium term.”
Additional information: As with any forecast, the content of the forecast throughout the process will evolve to take account of new information – for example, newly published statistics or any new policy decisions. It would not be appropriate to provide updates that run during this process.
“The Government is committed to working closely with the OBR. The Prime Minister and the Chancellor are meeting with Richard Hughes tomorrow to discuss the forecasting process and economic and fiscal developments since March. The Chancellor and the OBR will meet as usual throughout the prediction process.”