Trojan Horse school 'mistrusts' Birmingham City Council
"Mistrust and antagonism" exists between Birmingham City Council and a school named in the so-called Trojan Horse letter, a report has found.
Ofsted said senior leaders and governors at Adderley Primary School have become "distracted" by the breakdown in relations.
Inspectors called for both to "reinstate a functional working relationship".
The council said it was "working with the school" via a "buddy link system".
A spokesperson said Washwood Heath school - one of the authority's "outstanding schools" - was offering support to Adderley.
Adderley was one of the schools named in an anonymous letter outlining an alleged Islamist takeover plot in Birmingham schools was made public.
'Lack of communication'
The watchdog downgraded the school, in Saltley, from "good" to "requires improvement", in its latest report.
It praised the quality of teaching and the achievement and behaviour of pupils but criticised leadership and management.
The report identified a "breakdown in the relationship" between the school and local authority as part of the problem.
Inspectors said there was a "lack of clear and transparent communication" with the council, which meant Adderley was not "benefiting from... the oversight... usually expected in a maintained school".
"Steps should be taken to reinstate a functional working relationship" between the two, they added.
They also found school leaders were distracted by an "ongoing situation with regard to allegations made by former staff".Four women were arrested in April in connection with a fraud investigation at the school. They have been bailed until January.
The school was praised for its work to tackle "the risks associated with radicalisation and extremism" following their last inspection.
But, it said governors did not have a system to check these policies are being "implemented consistently".
Last month, Sir Mike Tomlinson was appointed education commissioner for the city - a post created after former counter-terror chief Peter Clark found evidence of an "aggressive Islamist agenda" in some city schools.
Ofsted is expected to publish the results of 40 no-notice inspections - including the five Trojan Horse schools placed in special measures - this month.