Labour has criticised Boris Johnson after an analysis of his flagship tax plan to cut rates for higher earners found that almost 80% of the people to benefit would be men.

Johnson, who chaired his first cabinet on Thursday, is still committed to raising the threshold for the 40p higher rate of tax from £50,000 to £80,000.

According to an earlier analysis by the Institute for Fiscal Studies, the plan would cost about £9bn a year and predominantly benefit the 10% of richest households in Britain.

Quick Guide 10 Boris Johnson leadership campaign pledges - and their costs Show 1: Raising the 40% income tax threshold Cost: £9bn. Only 12% of people in the UK earn more than £50,000 a year, so this pledge to move the 40% threshold up to £80,000 would help those on the highest incomes. 2. Increasing the starting point for national insurance contributions to £12,500 Cost: £11bn. At present people pay NICs when they earn £166 a week and income tax when they earn £12,500 a year. Johnson wants to gradually align the two systems by raising the NICs ceiling to an annual £12,500. 3. Raise education spending Cost: £4.6bn. Theresa May’s successor says he will raise education spending to £5,000 for every secondary school pupil and £4,000 for each primary school pupil. 4. More police Cost: £1.1bn. Johnson has promised an extra 20,000 officers. 5. Free TV licences for the over-75s Cost: £250m. This would reverse the BBC - and George Osborne's -decisions over this perk for pensioners. 6. Raising the level at which stamp duty is levied Cost: £3.8bn. There have been reports that the incoming prime minister would like all house sales under £500,000 in England, Wales and Northern Ireland to be exempt from stamp duty. 7. Nationwide full fibre broadband coverage by 2025 Cost: unknown. Industry experts say this is not feasible in the time available, given coverage is currently less than 10%. 8. The creation of six free ports in the UK Cost: unknown. Johnson said while on the hustings with Jeremy Hunt that he intended to create “about six” free ports – zones designated by the government to pay little or no tax in an attempt to boost economic activity. 9. Review HS2 and build HS3 Cost: unknown. One of Johnson’s big early decisions will be whether to scrap HS2 and spend the money on alternative rail infrastructure such as linking the big cities of the north through HS3. Any savings generated by scrapping HS2 will almost certainly be recycled into other transport projects. 10. Raising the national living wage Cost: unknown. The government employs one in six of the people working in the UK, so it would be affected by Johnson’s promise to raise the national living wage. Larry Elliott Economics editor

Labour had since commissioned research by the House of Commons library into the gender split of those who will benefit. It found that 850,000 women would gain from the increase in the threshold, against 2.9 million men, a split of 77% to 23%. This was the split for individuals rather than households.

The analysis, based on the IFS study, government population estimates and the EU’s Euromod tax-benefit policy simulation tool, also found that 80% of the financial benefit – the extra cash that will become available by raising the threshold – will go to men.

Dawn Butler, the shadow women and equalities minister, said the plan was emblematic of Johnson’s priorities.

“Women have borne the brunt of austerity. But rather than fixing the inequalities that are ingrained in our economic system, Boris Johnson’s plans will entrench them even further,” she said.

“If we design policies that benefit women as well, then everyone will be better off. A tax cut for the highest earners, the majority of them men, reveals just how misguided and out of touch Boris Johnson’s priorities are.”

The tax plan was Johnson’s first major policy announcement after he and Jeremy Hunt entered the final stage of the Conservative leadership race, where party members chose between them, and was seen as a bid for the backing of a membership that is disproportionately older and better off.

It immediately faced criticism, with the Resolution Foundation thinktank saying that 83% of those who would gain from the change come from the top 10% of households by income.

The thinktank calculated that someone earning £80,000 a year would gain by £57 a week, the same sum as that received in jobseeker’s allowance by a young unemployed person.

Given the response, Johnson has sought to play down the significance of the plan, saying it would form part of a wider package focusing more on helping lower earners.

Johnson has said tax cuts in general are a good idea as they end up increasing revenue – an idea based on a now generally discredited economic model.

However, with a working majority in the Commons of just two, in practice the higher rate tax cut seems unlikely to happen.