The school just yards from the Grenfell Tower blaze in west London will start the next academic year in temporary accommodation and might not return to its home until after Easter.
Kensington Aldridge Academy (KAA) has been closed since the fire at the 24-storey housing block on June 12 in which it is thought more than 70 people died.
In the immediate aftermath, nearby schools Ark Burlington Danes and Latymer Upper School opened their doors to hundreds of KAA pupils.
School leaders had hoped to move back into its building this September, but that is now looking “unlikely”, said its principal David Benson.
In a letter sent to parents last week, he said: “I have always been clear that we will not move back to our building until the tower has been covered and any investigations into what happened have been completed.
We did think that this could be in time for the new term, but this is now unlikely to be the case
“We did think that this could be in time for the new term, but this is now unlikely to be the case.”
Pupils will now use temporary classrooms 15 minutes’ walk from KAA, with transport provided for those who cannot walk or take the bus.
Benson said the temporary building was an “amazing” facility, which had the same number of classrooms as KAA, as well as specialist rooms needed to deliver the school’s full curriculum.
The timetable would run “as normal” – starting at 8.30am and ending at 3.30pm, with enrichment activities until 4.30pm.
The temporary accommodation was also “very close” to Ark Burlington Danes, which would continue to be available to KAA.
Benson said he could not tell parents exactly when KAA’s building would be back up and running, but it would be “at the right time, and we will manage the move back in the right way”.
He has been advised by the government that the latest date for return would be in April next year.
The education secretary, Justine Greening, and the national schools commissioner, Sir David Carter, hailed the “guts and bravery” of KAA leaders when they visited shortly after the blaze.
Other schools were also praised for rallying round. On the morning of the fire, Ark Burlington Danes – a mile away – made a makeshift exam hall in its atrium for KAA’s year 12 who had to sit an AS maths exam at 8.30am.
Even though many pupils were left homeless by the blaze, 55 of the 60 due to sit the exam turned up.
The school is now accommodating KAA’s years 7, 8, and 9 classes until the end of term.
Meanwhile, the year 12s, with 20 KAA staff, have been based at Latymer Upper School, about a 15-minute drive away in Hammersmith.
Staff and students at the schools were also among the scores of helpers coordinating the distribution of clothes and food, and have since been fundraising to help those affected.
A Just Giving page set up by a KAA teacher, Haley Yearwood, has raised more than £1.4 million.
“As I watched the news at 5 in the morning, I just wanted to make sure residents affected were well cared for after the tragedy,” Yearwood said. “Our school is in the heart of a fantastic community. The response so far has been overwhelming as money continues pouring in.”