The crisis at The Ridings school in Halifax culminated on Wednesday in an orgy of blame. There were plenty of candidates to carry the can - the teachers, the local authority, unteachable children and their feckless parents, union politics, a prurient press, moral and economic problems in society.

The danger, from the Government’s point of view, was that the extraordinary spectacle of a school spiralling into chaos and disintegrating before the eyes of the nation would be linked in the public mind with its own drive to increase selection, a policy at the heart of the Education Bill unveiled last week.

Presenting the inspectors’ report, which condemned every aspect of the school, Gillian Shephard made the link between bad behaviour and bad teaching, but was careful to apportion the lion’s share of the blame to the Tories’ traditional whipping boy - the local authority.

“All of this reflects very badly on the performance of Calderdale LEA which has neglected the school for two years,” she said, drawing attention repeatedly to a comment made by Calderdale’s director of education, Ian Jennings, on Monday’s Panorama, in which he admitted that the authority had failed the school.

“It is scandalous that any school should have been allowed to get into this condition I the law allows the governors and the LEA one last chance I and they had better get it right,” she admonished.

Politically, this was the only option left for Mrs Shephard. Blaming the teachers would have been too sensitive, given the current angst about discipline, and would have drawn attention to the fact that The Ridings has to compete with four selective opted-out schools, while blaming parents might have raised questions about social deprivation.

Mrs Shephard brushed aside questions about selection in Calderdale and, predictably, about the wisdom of reintroducing caning. So the school has been officially deemed to be failing and given just 18 working days to come up with a plan of action to prevent the arrival of a government “hit squad” or educational association. This is half the normal time allowed to schools under special measures. “This case is too urgent for such a leisurely timetable, ” she said. The governors must submit their plan by November 29; Calderdale has until December 6.

Mrs Shephard has also used her power to submit the school to fortnightly check-ups from Ofsted, and has asked the LEA to submit voluntarily to an Ofsted inspection, anticipating new measures on the inspection of LEAs introduced by the Education Bill.

Calderdale quickly agreed to be inspected and accepted a share of the blame, but protested at being singled out: “Her castigation of the authority is not reflected in the inspectors’ report,” said Michael Higgins, chair of the education committee. Last year, the council applied for Government money under the regeneration budget to address problems of social deprivation and educational underachievement in the area around The Ridings, but was turned down The OFSTED report was more even-handed in its condemnations. “Our view is that responsibility for the situation has to be shared between management, staff, governors and the LEA,” said OFSTED’s director of inspection, Mike Tomlinson, who led The Ridings emergency inspection last week.

Chris Woodhead, the chief inspector, was careful to stress the exceptional nature of the crisis at The Ridings, and also to avoid scuppering the school’s chances of recovery by condemning the teachers en masse. He praised a stimulating art lesson, but said that too many other lessons were boring, banal and undemanding. In one Year 7 French lesson, pupils had been asked to draw and colour in a table, writing “la table” beneath it, he said. In the OFsted report, the inspectors cite many other examples: “In a lesson on weather, Year 7 pupils were asked to draw and colour in a snowman, an activity that occupied most of the time.” The pervasive impression of boredom the OFSTED inspectors gained was reinforced by the filming by the Panorama crew.

Mr Woodhead said that he found “chilling” a sentence in the report that said senior staff had “lost the will” to improve matters.

On discipline, the report talks about the “volatile atmosphere”, with unsupervised pupils running wild in corridors and disrupting lessons. The constant presence of the media “appears to have further fuelled pupils’ excitement and unease”, and pupils alleged that they had been offered payment for interviews. Mike Tomlinson related a bizarre anecdote in which he and his Ofsted colleagues were out in the school grounds desperately trying to persuade pupils back into school after break and pupils responding with “raised-fist gestures”. It was soon after this that OFSTED decided that the school was out of control and should be shut.

Alice Mahon, the Labour MP for Halifax, was highly critical of Mrs Shephard’s decision to pillory the local authority. “The only piece of the jigsaw escaping inspection is Mrs Shephard.” No one denies that the school is failing, she said, but selection in the area undermined the school’s chances after the merger. A grammar school in every town will mean “a Ridings problem developing in every town”. But she said the OFSTED report gave a fair picture of the problem.

Meanwhile, Nigel de Gruchy, general secretary of the NASUWT, was celebrating the fact that his union had been the “catalyst” for the emergency inspection and the expulsion, on Tuesday night, of 12 of the worst pupils and the suspension of 23 others by the new head, Peter Clark. The union called off the threatened action on Tuesday night.

He dismissed suggestions that he had manipulated events to boost membership and publicity for his own union as “silly”. He said: “I do not scour the country looking for such things - we respond to calls for help.” He urged other teachers in similar situations not to wait to call in the union, and said he knew of half a dozen other schools with similar troubles. He laid the blame on the children: “We live in a topsy-turvy world that refuses to acknowledge that one of the fundamental reasons why it all began to go wrong at The Ridings lay in the horrendous behaviour of a small minority I everyone is blamed except the youngsters who started the problems.” But he said that he had no quarrel with the idea that incompetent teachers might have to go.