The independence of Ofsted is under serious threat from a parliamentary bill that could enable ministers to “meddle” with - or even abolish - the watchdog, headteachers have warned.

The Association of School and College Leaders (ASCL) has written to education secretary Michael Gove, criticising the inclusion of Ofsted in the new Public Bodies Bill, which would allow him to axe or change it at will.

In the letter, ASCL says it wants safeguards included in the bill to protect education organisations from ministerial interference.

ASCL’s sentiments were echoed by Lord Knight, former Labour schools minister, at a hearing of the bill earlier this month.

Calling the list of targeted organisations “the zombie list - the list of the living dead”, he said: “These bodies must be independent of government. The publication of Ofsted’s annual report, for example, was always a very difficult day for me as a schools minister because of Ofsted’s authority borne of its independence. How will they retain their independence when a minister can abolish them by order, thanks to the bill?”

ASCL’s inspections specialist Jan Webber said: “Not only does Ofsted monitor schools, it monitors government policy. We see this as a move that would jeopardise this by undermining its independence.”

The union’s general secretary Brian Lightman added: “Having any organisation in an undecided situation about its future makes it difficult to operate.”

But headteachers on the ground have questioned Ofsted’s current level of independence. Mike Kent, TES columnist and head of Comber Grove Primary in south London, said: “Since when was it independent anyway? I’ve always seen them as very government-dominated. I can’t offer any proof, but it does seem to trot out the Government mantra on data and safeguarding, for example.”

Ministers have already announced plans to narrow the focus of Ofsted inspections from 16 key areas to four: pupil achievement, teaching quality, leadership, and pupil behaviour and safety.

Among other quangos included in the bill is the Young People’s Learning Agency for England, which ministers said last week would be replaced with a new agency overseen by the Department for Education.

The School Teachers’ Review Body (STRB), which advises the Government on teachers’ pay, is also on the list, although no plans to change it have been announced.

A spokesman for the Department for Education said: “Inclusion in the bill simply means that changes can be made to arm’s-length bodies (ALBs) if this is required. It in no way undermines their independence.”

Ofsted declined to comment.

Lords on the warpath: Inclusions raise grave concerns

The Public Bodies Bill has caused outrage in the House of Lords because, as it stands, it allows junior ministers to abolish, merge or modify organisations established through an act of parliament.

Outcry followed the inclusion of the Judicial Appointments Commission in the bill, an act former Lord Chief Justice Lord Woolf declared “a matter of grave concern to the judiciary”.

The inclusion of the Independent Police Complaints Commission also sparked concerns about how it would retain its independence.

An amendment to the bill was passed last week to ensure that ministers could not make a decision to abolish public bodies that would be incompatible with judicial independence or human rights.

• Original headline: Bill’s powers reduce Ofsted to `zombie’. one of `living dead’