As leaders of the local authorities whose schools stand to lose the most under the government’s new funding formula, which is set to punish London schools, we must express our concerns (Poorer children half as likely to get into best schools – survey, 17 April).

The prime minister has spoken of her desire to enhance social mobility and to create a meritocracy in which every child has the opportunity to succeed; yet the new funding formula is set to reverse the significant progress that has been made.

The government’s own indices of multiple deprivation show that the net effect of the formula is to snatch funding from our poorest communities. Under these proposals at least £30m will be taken from the 30 most deprived local authorities in England. Rather than redistribute money away from some of the poorest pupils in our country, the government should look to replicate London’s success by levelling up funding elsewhere.

If the government is to have any credibility on the issue of social mobility, it must level up funding and ensure that no school in the poorest local authority areas will be made worse off as a result of its reforms.

Cllr Sarah Hayward Leader, Camden council

Philip Glanville Mayor, Hackney

Cllr Stephen Cowan Leader, Hammersmith and Fulham council

Cllr Claire Kober Leader, Haringey council, and chair, London Councils

Cllr Lib Peck Leader, Lambeth council

Sir Steve Bullock Mayor, Lewisham

Sir Robin Wales Mayor, Newham

Cllr Peter John Leader, Southwark council

John Biggs Mayor, Tower Hamlets

• Would someone please tell the Department for Education that patronising schools by offering support to manage their budgets is counter-productive and naive. Schools manage budgets, in general, very well. The issue is that competent, even frugal, budgeting is no longer sufficient to prevent deep cuts to staffing. I managed the budget of a school in one of the lowest-funded local authorities in England (Dorset) for a period in which we achieved four outstanding Ofsted grades and never created a redundancy or a deficit. That would be impossible now.

Kevin Banks

Blandford, Dorset

• Join the debate – email guardian.letters@theguardian.com

• Read more Guardian letters – click here to visit gu.com/letters