Brian Lightman, general secretary of the Association of School and College Leaders (ASCL) said:
While there is no excuse for complacency, you have to take into account how many rural and coastal schools are funded compared to inner city schools.
In the last decade, the intense focus has been on raising achievement in inner city schools, both in support and funding through the London and City Challenges.
The Pupil Premium has helped to address the funding gap to a certain extent but overall there is still a huge inequity in funding.
Schools in poorly funded authorities have less money to attract excellent teachers in key subjects, to buy in additional support and to reduce class sizes and teaching loads.
A Department for Education spokesman said they would consider Ofsted recommendations and respond in due course.