Ofsted would face major reforms under a Labour government, the party’s education spokesman has said, in a bid to remove the “politicisation” of the watchdog.

Tristram Hunt, Labour’s shadow education secretary, has warned that the inspectorate would need to undergo a serious overhaul if it is to remain trusted in its role as the school inspectorate.

Writing in a national newspaper, Mr Hunt added that headteachers and schools needed to be freed from political interference if the school system is to be improved as a whole.

The Labour frontbencher made a similar call for the removal of politics from education during a live webchat with TES last month.

Mr Hunt pointed to schools from “Norway to Singapore” that had been given the freedom to excel, focusing policies on improving leadership and teaching.

In today’s Observer, Mr Hunt writes: “Unfortunately, David Cameron jettisoned all that for relentless structural reform, curriculum instability and an assault on teachers as ‘enemies of promise’.”

But it was Ofsted that he said needs closest attention, stating that inspections needed to be “more radical”.

The watchdog had to move beyond “box-ticking and data dependence”, he added.

“Too much teacher workload is the product of preparing for an inspection,” he writes. “Yes, Ofsted must confront mediocrity, but it must also start to allow heads the space to innovate and develop a richer criterion of school achievement.”

He also claimed Ofsted had become too political. “It is not Ofsted’s place to adjudicate on whether schools have performance-related pay, whether a good school should be converted into an academy or to follow every ministerial fad on British values or otherwise,” Mr Hunt writes.