Boris Johnson is planning to slash income tax for more than three million people by increasing the threshold for the 40p rate to £80,000 if he becomes prime minister.

Mr Johnson has drawn up radical plans to increase the point at which people start paying the higher rate of income tax from £50,000 to £80,000, pulling hundreds of thousands of people out of the 40p band entirely.

The move, which will cost an estimated £9.6 billion a year, will save people thousands of pounds on their tax bill. It will be funded from the £26.6 billion of "fiscal headroom" that is currently set aside by the Treasury for no-deal preparations.

The approach is intended to help "stimulate" the economy as the UK leaves the European Union on October 31. Mr Johnson has said Britain must leave with or without a deal on that date.

Writing in The Telegraph, the former foreign secretary gives a clear indication of his approach. He says: "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."