Parents planning on sending their children to the 'inadequate' Ecclesfield School have been left shocked after it was placed into special measures.
Despite the school's overwhelming popularity, Ofsted inspectors concluded it had "declined considerably" in the last three years before criticising the teaching and pupils' achievement.
Just this year the high school was found to be one of 13 oversubscribed in Sheffield with many of its pupils arriving from nearby Ecclesfield Primary School.
However, speaking after the release of the damning report, many parents of children at the primary school expressed their surprise and worry at the news.
Stacey Pickersgill said she had two children at the primary school with her eldest due to start at the high school in September.
She said: "A lot of parents have been surprised by the report because it's supposed to be a really good school.
"It's made me doubt my decision to send my son there but there's not a lot I can do now.
"It's very worrying and the headteacher has now sent a letter out to parent about how shocked and upset they are.
"There's four years between my children so they've got a while to bring it back up to standards. There's a lot of good things going on at the school but this is sure to have a big impact."
Ecclesfield School was ranked 16th out of the city's 26 secondaries by the latest Progress 8 measures - which measures the amount of progress youngsters make between leaving primary school and finishing secondary school.
Although the report came as a shock to two parents speaking outside the primary school, they stressed it would never put them off sending their children there.
Clare Elston said: "My kids absolutely love it there. The staff have gone above and beyond to help them. I'm so surprised that I might even put in a complaint to Ofsted.
"My eldest has Aspergers and, even before he started, the staff were sending him timetables to help him prepare for the start of school."
Natalie Woodward said: "I went there when I was a kid so it would never put my kids off going there. The teachers are lovely, you just have to phone up and they can't give you enough help.
"They are so caring in regards to their pupils. You can't always listen to what Ofsted say and I don't pay any attention to it.
"Anyone with common sense doesn't listen to Ofsted so it shouldn't impact them."
Headteacher Joel Wirth said he was ‘deeply shocked’ at the damning Ofsted report and defended his school, but stressed that it would address the issues raised.
He raised concerns that the report could affect the community’s confidence in the school and deter some parents from sending their children there.
However, one grandmother picking up her granddaughter said the report should not deter parents from sending their children to the "wonderful school".
She said: "I have nothing but praise for it, my eldest grandaugher goes there and she is doing extremely well so it would not put me off at all as a parent.
"I would need to see the full report but, from my experience through my eldest granddaughter, I'm very surprised by it as I can't praise it enough."
Simon Lowe, who has two children at the primary, agreed that the report would not raise any doubts over the school's success.
He said: "I've got two kids here but it's not going to make me change my mind because my other daughters go there.
"I wouldn't pay too much attention to it anyway, as long as she gets her GCSEs then thatt's fine. They really enjoy it there, that's what makes it so surprising."
As well as sending letters out to parents with children joining Ecclesfield School, parents revealed that the high school was also holding an open day to address any further concerns.
Despite the damning report, parent Peter Smith blamed the lack of Government spending for the tough situations many schools were now facing.
He said: "The school does have a lot to answer for. But, it boils down to finance and government spending, if that falls, everything falls.
"The report is not a problem for me, I will just speak to them face to face and I would want them to get back to me personally, I would not just take Ofsted's word for it.
"I'm unaware of any problems there and there are a lot worse schools in the area that need a lot more work."