The huge disparity in per pupil funding across Lincolnshire's 52 secondary schools has been laid bare in new government data.
Concerns have been raised over the Government's plans to reform education funding, with researchers fearing that many schools will be no better off under the new framework than they were a decade ago.
The Queen Elizabeth's High School in Gainsborough was allocated the lowest per-pupil sum of £4,565, meaning its 943 students receive 40 per cent less funding each.
The new experimental figures cover all state-funded maintained schools and academies in England.
Schools funding comprises budgets set by the local authority alongside cash from government grants. The current system, in which budgets are set according to what has been awarded historically, allows for huge differences in how much funding pupils living in different areas of the country receive.
A national funding formula, first announced by the Government in 2016, will replace more than 150 different formulae with one nationwide system.
However, the Education Policy Institute think tank says the new approach could direct extra cash towards more affluent schools which "risks widening the education attainment gap".
Jon Andrews, deputy head of research at the EPI, said: "Schools have seen growing pressures on budgets in recent years. Between 2009-10 and 2019-20, school funding per pupil fell in real terms by around eight per cent.
“The Government's plans would reverse these school funding cuts, but that would still mean that per pupil funding in 2022-23 is no higher in real terms than in 2009.
"The Government has vowed to ‘level up’ school funding, by increasing the minimum level of per pupil funding that primary and secondary schools receive. This approach will, however, disproportionately direct additional funding towards more affluent schools with the least challenging intakes."
The minimum per-pupil funding levels in 2020-21 will be set at £5,000 for secondary schools, while primary schools will get a minimum of £4,000 per pupil from 2021-22 says a DfE spokesman.