Tory leadership contest: Boris Johnson vows to cut income tax for people earning more than £50,000 a year

Boris Johnson has vowed to cut income tax for people earning more than £50,000 a year if he wins the Conservative Party leadership race.

The former Foreign Secretary told The Telegraph that he would increase threshold at which workers start paying the 40p rate from £50,000 to £80,000 - a move set to which would cost around £9.6bn a year.

Johnson said he would find the cash from a contingency fund set aside by the Treasury to pay for the impact of a no-deal Brexit.

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The pledge came as fellow Tory leadership candidates Jeremy Hunt, Dominic Raab, Michael Gove and Matt Hancock prepared to formally launch their own campaigns for the top job.

Writing in the Telegraph, Johnson said: "We should be cutting corporation tax and other business taxes.

"We should be raising thresholds of income tax – so that we help the huge numbers that have been captured in the higher rate by fiscal drag. We can go for much greater economic growth – and still be the cleanest, greenest society on earth."

According to the paper, the pledge will be funded using some of the £26.6 billion of "fiscal headroom" currently set aside by Chancellor Philip Hammond to prepare the UK for a no-deal Brexit.

It comes as four other contenders for the leadership prepared to urge Conservative MPs to back them over Johnson, who is currently the frontrunner in the race to succeed Theresa May.

Gove, who is under mounting criticism after admitting to using cocaine in the past, will take a swipe at Johnson and say Brexit requires "a serious leader".

"This moment - right here, right now - is a serious time in the life of our nation," the Environment Secretary will say.

"And it requires a serious leader. The stakes have never been higher, the consequences have rarely been greater."

Meanwhile Hunt - who received a boost as he was endorsed by fellow Cabinet minister Amber Rudd - will also try to contrast himself with Johnson as he warns against picking a leader reliant on "empty rhetoric".

The Foreign Secretary will say: "We are facing a constitutional crisis. Our new Prime Minister will preside over a hung Parliament.

"This extremely serious moment calls for an experienced, serious leader. We need the art of tough negotiation, not the art of empty rhetoric."

Former Brexit Secretary Raab will unveil plans to shift £500m a year from the UK's aid budget in a bid to boost spending on protecting endangered species and habitats.

He will say: "We've got to look to the future. We've got to leave the environment in a better state than we found it."

Meanwhile Health Secretary Hancock will position himself as offering a "fresh start" for the party and vow to boost the National Living Wage to £10.21 by 2022.

Launching his campaign in London, he is expected to say: "I refuse to be the leader offering simplistic or populist solutions. Instead, an emotionally charged platform to improve lives, rooted in objective fact."

And he will add: "My mantra is 'move fast and make things happen."

Tory hopefuls having until 5pm on Monday to formally enter the race to become party leader, and must have the backing of at least eight MPs to join the contest.