Delegates at the National Union of Teachers (NUT) conference in Brighton backed calls for the schools watchdog to be ditched, saying it simply added to anxiety with little scope of improvement.

Members voted to speak with the Labour Party to lobby for a new system, and will ask it and any forthcoming Labour government to scrap Ofsted as part of a shake-up of education regulation.

Teacher Mark Slatter, from West Sussex, seconding the motion, said his school was “expecting the dreaded phone call, any time now, saying Ofsted will be coming”.

He said: “Even before they arrive, my head teacher informs me that we cannot get ‘outstanding’ or even ‘good’ because of past and predicted results,

“What kind of system prejudges a school and assumes it requires improvement before it even steps over the threshold?”

He said teachers in departments in need of improvement have not been given any indication on how they can become better.

NUT Executive member Amanda Martin, presenting an amendment to continue to build support for alternative models of school accountability, described Ofsted as “the big bully, the ogre, the workload creator, who causes anxiety, fear and worry, the ever-circling vulture that is Ofsted”.

She said: “The amendment calls for Ofsted to be abolished. Not because we don’t want to be made accountable, but simply because it is not fit for purpose.”

The motion described Ofsted as “a political tool”, “used increasingly to drive a narrow and reactionary vision of education”.

It said the watchdog had “no place in any proper system of school accountability” and should be immediately stopped.