Ofsted is “winning the argument” in its battle to secure the power to inspect academy chains, chief inspector Sir Michael Wilshaw has claimed.

In recent months, the inspectorate has swooped in to visit multiple schools operated by some of the country’s biggest academy chains and has expressed concerns about standards in some schools operated by E-Act, the Academies Enterprise Trust and the School Partnership Trust Academies.

But Sir Michael has long argued that Ofsted should also be able to inspect the central services of academy chains, in the same way that it inspects local authorities.

“We want to adopt the same approach to academy trusts and chains,” he told a press conference on the launch of the watchdog’s new framework consultation today. “At the moment we inspect the constituent schools of those academies we perceive to be weak, but we do not have the necessary powers to look at the centre…We want a level playing field.”

When asked whether he was making headway in persuading the Department for Education to award Ofsted extra powers, he responded: “I’m winning the argument”, but refused to elaborate.

Sir Michael also claimed that the introduction of more frequent inspections for good schools would “sharpen headteachers’ act up”, by forcing them to improve their self-evaluation processes.

Mike Cladingbowl, Ofsted’s national director for inspection reform, said the move would encourage schools not to “prepare unnecessarily for inspection”.

“What these inspections will do, we believe, is to create a different kind of climate and context,” he said. “Whereby [an inspector] coming into the school is more of a norm than it is now. We’re out to encourage less specific preparation for a grand Ofsted event, which is cliff edge at the moment for many schools. It’s very much a make-or-break event for them. This [new model] is a different kind of inspection.”

Sir Michael also insisted that the day and a half-long visits would still be allow enough time to identify outstanding schools.

“You can spot a good school within half an hour actually,” he said. “I can say that as an experienced head…People are busy in the classroom, the children are focused and energised and are really getting on with their work. You can spot that very quickly.”

Related stories:

Ofsted announces another U-turn over no-notice inspections - October 2014

Ofsted launches wave of no-notice school inspections - September 2014

Ofsted scraps grades for individual lessons - August 2014

Ofsted must scrap ‘quality of teaching’ from inspections - July 2014