The introduction of such a measure would see millions of households paying a fifth less in income tax, with those on the average UK salary of £32,000 saving approximately £777 per year. Sunak said this would be the “largest cut to income tax in 30 years” and called the move “responsible.”

The former chancellor said the commitment would be delivered by the end of the next parliament if he wins the Conservative leadership race.

Speaking to BBC Radio 4’s Today programme, Sunak said, Now the last week or so of this contest we’ve been focused on the here and now about how best to fight inflation and I think everyone knows where we stand on that and we have different points of view.”

“But, as chancellor, I was very keen to make sure that I started cutting taxes and what I’ve announced today builds on that and that’s because I believe in rewarding work and the best way for the government to signal that is to cut people’s income tax.”

"And in this parliament as chancellor, I already said we’re going to cut income tax for the first time in almost 15 years and, as prime minister, I want to go further than that and cut income tax at the basic rate by a fifth to 16p, but I want to do that in a way that’s responsible.”