Inset days are “universally reviled” by teachers and largely used for keeping school staff up-to-date with policy changes rather than for professional development, school leaders and education experts have warned.

The five statutory days per year, during which schools remain closed for staff to take part in in-service training, are rarely used to reflect on and develop teaching practice, with “most” schools unsure how to make best use of them, a roundtable discussion on CPD concluded.

The event in London, hosted by the NAHT heads’ union, was organised to generate debate ahead of a Department for Education consultation on the future of CPD, which is expected to begin this autumn.

NAHT general secretary Russell Hobby said there was a “sense of dissatisfaction” among school leaders and teachers about how CPD is currently managed in schools, and claimed the Inset day was a particular source of frustration.

Paul Crisp, managing director of the Centre for the Use of Research and Evidence in Education, said Inset days were the “most common but least useful” weapon in schools’ CPD armoury. “On the basis of our evidence, it’s universally reviled,” he added.

Sion Humphreys, policy advisor for the NAHT, told the meeting that, as a deputy head, his school had been barred by the local authority from using three Inset days for extended and more in-depth CPD sessions,  “There’s a real compliance and control model that frustrates innovation,” he said.

Louis Coiffait, chief executive of the new NAHT Edge union for middle leaders, said many Inset days ended up being used to update teachers on policy changes and internal management.

“Teachers get those kind of in-school, quick meetings about this change, that change; if you’ve got so many changes coming in, you can see how that would be a very difficult environment to have a sustained [CPD] framework around,” he added. “It also creates a situation where you really need it more than anything to help you cope with change.”

But Nansi Ellis, head of education policy and research at the ATL union, cautioned against calling for the days to be scrapped altogether. “I don’t think we could say get rid of Inset days because I don’t think our members would support that, even though they’re not particularly beneficial in CPD terms.”

Professor Toby Greany, professor of leadership and innovation at the Institute of Education, argued that CPD opportunities were being thwarted by a lack of coordination between schools. “Some schools get it but many if not most, and don’t see development of staff as the core mechanism for improving quality and outcomes and everything else,” he said.