The principal of the online Oak National Academy has said he “didn’t expect it to go as big or as far as it’s gone” with new figures suggesting nearly half of teachers have used the school.

A poll of 3,000 teachers by Teacher Tapp found 46 per cent have used Oak, which extrapolated across the country, means more than 225,000 staff.

In an end-of-year interview with Schools Week, Matt Hood said he initially thought the platform would be “small” and run “for a term, maybe”. It was set up in weeks at the start of the pandemic to provide lessons for pupils during lockdown.

But the academy has become a household name, with nine million lessons delivered since September.

New research also shows how it helped schools in the worst-hit Covid areas. The top ten areas to use the platform by population are Blackburn, Rochdale, Walsall, Bury, Halifax, Wigan, Bolton, Burnley, Stockton-on-Tees and Dudley – all towns in the north and Midlands.

Three weeks after it was announced that Manchester, Liverpool, Nottingham, Leeds and Sheffield were going into tier 3, use of Oak in those areas increased 60 per cent on average.

After an initial £500,000 from the government to launch in the spring, Oak received an additional £4.3 million to continue providing online lessons into this academic year.

But in terms of what happens post-pandemic, Hood said Oak’s leaders were “in the foothills” of those conversations. The academy’s future would depend on whether the profession wanted it to continue, and whether it could find uses for its services unrelated to Covid.

“If both of those tests are met, and we can find a way of making the organisation sustainable that would be something that is really exciting.”

Some schools have used Oak resources to prepare staff due to cover lessons for absent teachers, while others have used them to help with non-Covid-related pupil absences.

And some early career teachers have watched lessons as part of their professional development, while the Ministry of Defence has used them in schools for the children of service personnel.

But Hood said he wanted to “hear and understand more” from teachers and leaders, and added that the academy was still “way off” questions about how it could be funded and run in future.

The Oak principal also praised the 350 teachers who created lessons for the platform.

“Those nine million lessons, the graft, the hard work and the expertise that’s gone into those is all from teachers dotted across the country,” he said.

“We have brought them together, coordinated their efforts and shared it more widely. And we’re really proud of that role that we’ve played, but it’s small by comparison to the work that they’ve done.”