Registered inspectors found 77 per cent of teaching at Langham school in Tottenham, north London, was satisfactory or better, compared to 50 per cent in March when HM inspectors visited it.
Gillian Shephard, the Education and Employment Secretary, is soon to rule finally on her move to send in an educational association to the school, deemed failing by the Office for Standards in Education.
Langham has been at the centre of a row since inspectors criticised poor management three years ago. The head was later sacked, and last November the school was found to be improving, but in March inspectors said its progress was too slow.
Governors of the school, in which around 80 per cent of pupils speak English as a second language, are campaigning against the hit squad. They say Langham has made good progress since March, when a new acting head was appointed and a rigorous action plan adopted.
The announcement last month, which would mean Langham becoming the second school to be taken over by a hit squad - the first, Hackney Downs, was closed last year - angered governors, teachers and parents.
They are campaigning against the decision - a demonstration on Saturday, addressed by local MP Bernie Grant, attracted around 150 parents.
The school, in its response to the Department for Education and Employment's hit squad proposal, says it has made a "vast improvement" in many curriculum areas since March.
Discipline has improved and staff development is occurring on an unprecedented scale, it says, adding that the announcement of an education association had a potentially devastating effect on the school, with the intake of new pupils slowed and staff recruitment for next year "totally sabotaged".
Two inspectors registered with OFSTED were commissioned by Haringey council, Langham's local authority, to carry out the latest inspection.
They spent four days at the school last week and observed 30 lessons - compared with 18 seen by OFSTED inspectors in March. They said all teachers had established good routine classroom procedures and have "clear and appropriate expectations" of pupils' behaviour.
Relations between staff and pupils were good, and in the best lessons teaching was clearly focused on pupils' learning.
Some lessons did not take account of the full range of pupils' abilities, but the inspectors concluded: "The school is to be congratulated on the evident progress that has been made in improving the quality of teaching over the last few months."
Acting head John Beighton said: "We're delighted that it vindicates the work we have done in the last three months.
"It would be much better if the school were allowed to continue to improve rather than a hit squad being sent in, which would be very detrimental. "