The Daily Telegraph has reported that in a letter to a retired financial adviser shadow commons leader Theresa May let slip that the Tories are looking to propose an IHT threshold of £1m per person.
This means that it would be possible for a married couple to enjoy a threshold of £2m.
Rival political parties have been quick to lash out at the proposals, with Labour questioning how the Tories could justify more tax cuts for millionaires.
Yvette Cooper, chief secretary to the Treasury, says: “David Cameron clearly tried to hide this but now we know the Tories’ priority is to give money to a few thousand of the wealthiest in the country. How can this be fair?”
The current IHT threshold for couples is £600,000.