Mr Kwarteng and Ms Truss are reportedly considering accelerating the 1 cent income tax cut – a cut in the base rate from 20 cents to 19 cents in the pound – currently slated for 2024.
Mr Sunak confirmed the move when he was chancellor earlier this year and it is rumored that the move will now be accelerated.
Ms Truss has also reportedly considered raising the income tax threshold at a higher rate of 40 per cent to £80,000 from the current £50,270, something her predecessor Boris Johnson promised to do in 2019.
Someone making £80,000 would save £6,789 a year if Mr Kwarteng raised the income tax threshold this week, along with reversing the National Insurance increase.
Anyone making £60,000 would save £2,539 a year, but below this income threshold the savings would be minimal. Someone with £50,000 would save £468 a year, while someone making £30,000 would save just £218.
The inheritance tax brought in a record £6.1bn to the government in its most recent tax year, with millions of families caught on the hated tax due to the freezing threshold and higher property prices.
It was once seen as a burden on the wealthy, but Ms. Truss promised an estate tax review during her leadership campaign to prevent ordinary households from being stung by the death tax.
Mr Shah said: “Party members and traditional conservative voters have a deep disdain for estate taxes, and Ms Truss may be tempted to abolish it entirely.
“But something should take its place and calls for a wealth tax could be revived. Capital tax reforms would require detailed deliberation, and the government may not have enough time to do something so dramatic with the next election scheduled for spring 2024.”
An extension of the marriage allowance is one of the more generous tax gifts mooted by Ms. Truss that will benefit lower earners more than wealthier families.
In July, she announced plans to allow couples to transfer their full personal tax deductions, the amount a person can earn before paying income tax, among themselves if she becomes prime minister.