Haringey Borough Council says it is "disappointed" a teaching unit for vulnerable children failed its Ofsted inspection.
The pupil referral unit, which is split between a primary school in Muswell Hill and a secondary school in Wood Green, was judged inadequate by Ofsted last month.
The report said pupils did not make progress quickly enough, particularly in English and maths and teachers did not have high enough expectations of what pupils can achieve.
A council spokesperson said: “We are disappointed with Ofsted’s findings about the secondary pupil referral unit, which we have recently given extra resource to help support rapid improvement. However, we are pleased by the recognition given to our primary unit, which is good with outstanding features.
“Our ‘Outstanding for All’ commitment to education is that all Haringey schools will be rated good or outstanding by Ofsted.
“We will be reviewing our plans to ensure we meet this commitment as soon as possible for the unit, which provides vital education and support for children and young people who face significant challenges.”
The unit aims to support pupils and get them back into mainstream school, further training or employment depending on the age of the child.