Repairs on a school whose pupils wrote to David Cameron to lobby over "unsafe" classrooms have been completed.
Pupils from Rose Hill Primary School delivered letters to Downing Street in 2015 over problems with "broken lights" and "smelling mouldy ceilings".
Children had to wear coats during lessons in winter after a boiler broke and temperatures dropped to 8C (46F).
Headteacher Sue Vermes said the end of the £1.3m refurbishments was the "start of another" chapter for the school.
During the winter months, the school in Oxford had to put foam around some windows to prevent heat escaping.
One child wrote to the former prime minister saying: "I'm writing to you to tell you there are broken windows and our building is falling apart."
The government said at the time local authorities were responsible for school maintenance and it had already given £35m to Oxfordshire County Council to repair and improve its schools.
Korky Paul, an Oxford illustrator whose work includes the Winnie The Witch books, marked the end of the project which has seen windows, doors, lighting and floors replaced throughout the building.
Ms Vermes said: "It felt like today was the end of one part of the school's story and the start of another, so it was fitting to have such a major figure in children's literature here to help us celebrate."
The £1.3m repairs were completed after the primary school joined Oxford-based River Learning Trust 18 months ago.
River Learning took on the school which had "struggled" to find an academy trust due to the cost of the repairs.
The school became an academy after being placed in special measures by Ofsted in January 2016, but has since been taken out in 2017.