Staff at Cotham School in Bristol used to patrol a row of shops nearby after home time between 2.45pm and 3.15pm.
Teachers had told pupils they couldn't go into the shops in this period but they acted like "guards" in an attempt to enforce this.
But the kids are now allowed to tuck in - after Neil D'Souza, the irate owner of takeaway Chilli Bellies, called Avon and Somerset Police .
The school insists their original move was praised by parents but has nevertheless done a dramatic U-turn in the last couple of days.
Mr D'Souza said: "They came in the shop and started telling off the children who were in there, handing out detentions, demanding that they leave.
"I’d taken the children's money, their food was almost ready. I said I’d had enough and asked this teacher to leave, to get out of my business, get off my property.
"He argued with me, and then went and stood right on the doorstep. He was physically blocking the entrance. They were intimidating the students, and this was intimidating to my normal customers too. He refused to move, that’s why I called the police."
Local resident Kate Grant also tried to enter the shop - and also challenged the teachers.
She said: "You’ve got two senior teachers in high-vis jackets standing outside a shop like bouncers. This is after school, with the kids on their way home. Young people have a hard enough time as it is."
But the school's statement said today: "Following a large amount of interest in the press regarding how Cotham School has chosen to take measures to safeguard our students in their immediate onward journey home through narrow streets and over pedestrian crossings, we have decided to issue this statement to provide accurate rather than distorted information.
''Cotham School is a large school with more than 1,500 students and over many years members of staff have assisted our students in their journey home by walking part of the route with them immediately after school as part of their after school duty.
''During this time we have received positive feedback from our parents, carers and Cotham residents who have welcomed and supported us in this.
''However, our decision over the last few weeks to advise students that they should not use the shops located on the route between Cotham School and Nine Tree Hill between the times of 2.45pm and 3.15pm, in order to further assist their safe passage home through what is a very compact and urban area has been met with a mixed response."
More than 1,500 pupils attend the school, rated as "Good" by Ofsted in the last inspection.
The school added: "Most of the feedback received has been very supportive of the school’s decision but some has been less so.
''Having taken all of the views received into consideration we will still continue to support our students in remaining remaining safe as they leave school via Cotham Road and move forward on their onward journey home.
''However, we have decided that we will no longer provide a staff presence in the vicinity of the shops.
"We have listened to the feedback received from both sides of the debate and we will therefore be reaching out to local councillors and Cotham residents so that we can meet together and talk about both the good work of the school and its students and the very good work that the community undertake.
''The meeting will focus on how we may work together for the benefit of the school and Cotham residents.''