Chancellor Rachel Reeves must not “pull up the drawbridge to international students” by imposing a tax on their university fees, Sir Sadiq Khan has warned.

The London mayor, on the second day of a trade trip to Africa, said such a move would be an “act of immense economic self-harm” that would damage London and the wider UK economy.

It is his latest “red on red” clash with Labour colleague Ms Reeves in the wake of the comprehensive spending review that Sir Sadiq criticised for failing to invest in new transport projects.

Prior to setting off for Africa, Sir Sadiq told business leaders last Thursday: “We can’t afford this government to be anti the capital city like the last one was.”

Ministers proposed in the Government’s flagship immigration White Paper imposing a levy, possibly at six per cent, on universities’ income from international fees and cutting graduate visas from two years to 18 months.

The White Paper stressed there were problems involving “misuse and exploitation of student visas”, and that “too many graduates” are remaining in Britain after their studies while not moving into graduate level jobs.

On Tuesday, London fell from first to third place in the QS Best Student Cities Ranking 2026, behind Seoul and Tokyo.

Sir Sadiq, speaking in Accra to students at Imperial College London’s new Ghana hub, said the proposals would also damage university finances and be “an act of immense economic self-harm”.

City Hall projections put the annual economic benefit of overseas students at UK universities around £55bn, including £12.5bn from those based in London. Five per cent of London university students are from Africa.

Sir Sadiq was expected to say: “There are people at home who believe we should pull up the drawbridge to international students, or punish universities that choose to welcome people from around the world.

“Closing our country to global talent would be an act of immense economic self-harm – one that would slow down growth and leave working people in Britain worse off than before. That’s why I’m calling on our Government not to make it harder for international students to study in the UK.

“On my watch, London will be as open as ever… but I think we must do more. We cannot simply wait for the world to come to London; we must bring London to the world.”

The graduate visa route was launched in July 2021 as an unsponsored way for students to stay in the UK for two years (or three years for PhD students) after graduation.

The aim of the route is for international student graduates to work, or look for work, following the successful completion of an eligible course.

Imperial College London president, Professor Hugh Brady, said: “International students are an essential part of Imperial’s global community. They bring diverse perspectives, new ideas, and fresh approaches to tackling today’s most complex challenges.”

London Higher chief executive Liz Hutchinson said: “This is a time when we should be strengthening our position as a hub for talented individuals from across the world. The government’s proposed levy on international students does the opposite.”

Universities UK chief executive, Vivienne Stern, said: “We are fortunate to be a destination of choice for students from all over the world. We should be proud of this and work hard to make sure that international students feel welcome.”

John Dickie, chief executive of lobby group Business LDN, said: “At a time when some of our rivals are closing their doors to international students, the UK should do all it can to reinforce its attractiveness to talented people from across the globe.

“London is the world’s best city to study, but the Government’s plans to introduce a new levy on the income generated by overseas students risks damaging our competitiveness. Ministers should scrap these plans to avoid damaging growth, exacerbating the higher education sector’s financial challenges and undermining our soft power.”