Greenwich's first free school requires improvement in teaching and leadership, Ofsted inspectors say.
The Greenwich Free School (GFS), based in Shooters Hill, opened in September 2012 with 100 pupils and has since taken on 100 more. Praised by Michael Gove, it immediately made headlines with a zero-tolerance approach to mobile phone use by pupils.
But its first ever Ofsted inspection has revealed concerns over pupil achievement, teaching quality and leadership.
In their report, inspectors wrote: "Too few students make good progress across the different subjects taught in the school.
"Lower-ability students fall behind in some lessons because the teaching does not cater for their needs."
And they said: "Leaders monitor teaching regularly but they do not focus sufficiently on the impact of teaching on students’ learning over time.
"In the school’s first year, arrangements for checking students’ progress did not provide leaders or governors with an accurate view of the school’s performance."
But elsewhere in the report the school - whose first head teacher Lee Faith left after just a year at the helm - is praised for its curriculum, pupils' personal development and their good behaviour.
A new head teacher Oliver Knight, the founding vice principal of the renowned Ark Academy, is due to take over this June.
The school said in a statement: "We're pleased that the two inspectors highlighted a few of GFS's excellent features - including our pupils' behaviour, the design of the curriculum, the great extra-curricular activities and the strength of the governing body.
"But we're obviously disappointed in the overall conclusion the inspectors drew from our first year's internal data - and were surprised by how markedly it differed from the various feedback GFS has otherwise received from parents and visiting educationalists.
"Nevertheless, the senior leadership team and governing body take the inspectors' views - like all feedback - very seriously and GFS's new headteacher, who was appointed shortly before the inspection to start work later this term, will be overseeing GFS's continued progress and response to the inspectors' findings.
"Everyone at the school will continue to work hard to deliver an excellent education for every pupil - and we look forward to practising the very 'growth mindset' we see in our pupils, as we continue to grow."