Chancellor Rishi Sunak has reassured recently elected Tory MPs there will not be a “horror show of tax rises with no end in sight”, as the government deals with the costs of coronavirus.
He urged the 2019 Conservative intake to show trust to overcome the “short-term challenges” the party faces.
Some MPs have expressed fears U-turns are hurting the government’s standing.
Mr Sunak accidentally revealed the wording of his statement while holding his notes outside 11 Downing Street.
The Conservative Party, which won an 80-seat majority over Labour at December’s general election, has seen its poll lead over the opposition cut in recent weeks.
This has led to concerns among MPs who seized constituencies in traditional Labour heartlands in the Midlands and northern England, known previously as its “red wall”.
One unnamed senior Conservative MP told the Press Association their colleagues there, and in other marginal seats, were becoming “jittery” following a series of U-turns on subjects including exam results, the wearing of face coverings and school meal funding. They described the situation as a “megadisaster”.
And Sir Geoffrey Clifton-Brown, treasurer of the 1922 Committee of Tory MPs, warned against “own goals”, saying: “We may have a big majority but that still doesn’t mean to say that we shouldn’t be as competent as possible as a government.”
It was reported at the weekend that substantial corporation tax rises and capital gains tax changes are being considered by the Treasury to deal with the enormous costs of coronavirus. But the government dismissed this as “speculation”.
The wording of Mr Sunak’s statement, read out during a meeting on Wednesday with Tory MPs first elected in 2019, which the prime minister also attended, was revealed when a photographer noticed the chancellor holding a script sheet while leaving 11 Downing Street.
It read: “We will need to do some difficult things, but I promise you, if we trust one another we will be able to overcome the short-term challenges.”
Referring to the reports that there could be tax increases to pay for costs incurred during the pandemic, including the furlough scheme, it added: “Now this doesn’t mean a horror show of tax rises with no end in sight.”
It continued: “But it does mean treating the British people with respect, being honest with them about the challenges we face and showing them how we plan to correct our public finances and give our country the dynamic, low-tax economy we all want to see.”
Government sources denied the revelation of the chancellor’s words in this way was “embarrassing”, adding that they would have become a matter of public record anyway.
Boris Johnson faces a meeting of all backbench Conservative MPs later on Wednesday, when the 1922 Committee gets together for the first time since Parliament’s summer recess.