So says Sir Irvine Patnick, Tory MP for Sheffield’s Hallam constituency, a large middle-class enclave in a city where Labour has been king for longer than most people can remember.

The “it” in question is the state of one of the constituency’s schools, Silverdale, which last week sent home 500 of its 1,150 pupils after council health and safety officers advised that the entire top floor of the main building was unsafe.

The head, Enid Fitzgeorge-Butler, had called in the council after extensive leaks to the flat roof, exacerbated by bad weather, flooded a classroom and brought down the ceiling in the staffroom. A heating system, installed just two years ago, failed, forcing teachers and pupils in the history and maths departments to work in coats and gloves.

These are just the most dramatic signs of neglect in a school, system-built in the late 1950s, which like many others in the country has outlived its intended life-span. Everywhere one looked, as an army of repair men worked through last weekend to make the top floor fit to re-open, there were signs of deterioration: a crumbling concrete roof support, plasterboard missing from classroom walls, a fire-door in the room used by the head of maths which had come away from its frame and would not close.

Mrs Fitzgeorge-Butler says she decided to send children in Years 7, 8 and 9 home because, as head, she had a duty to care for the safety and interests of her pupils and staff. The physical state of the school, where she has been head for two years, was the worst of any she had worked in during 25 years as a teacher. Staff morale was low and the health of children and staff was suffering owing to the broken heating system and persistent condensation.

In many ways Silverdale is typical of many other crumbling schools around the country. The local education authority puts the blame on years of underfunding by successive Tory governments, which has forced councils to cut back on maintenance programmes and new school-building projects.

Jan Wilson, the council’s chair of education, insists Silverdale, which reopened on Tuesday, is not the only Sheffield school with severe problems.Her advisers calculate that #163;37 million needs to be spent to bring the council’s school buildings up to scratch. This year, however, the Government allowed the council to spend only #163;260,000 on capital projects. The capital spending settlement by the Chancellor Kenneth Clarke last week - #163;50m, to be shared out among more than 100 LEAs - means the city is unlikely to be able to tackle its backlog of repairs.

Two things make Silverdale’s plight more than just another crumbling school story. The first is a long-standing coolness between the council and a group of Sheffield’s most successful schools, including Silverdale, which in the late 1980s successfully fought off a plan to axe their sixth-forms as part of a plan to set up a city-wide tertiary colleges system.

Old wounds were reopened last week when Sandra Tomlinson, chair of the Sheffield Association of School Governing Bodies, which represents most schools in the city, criticised Mrs Fitzgeorge-Butler’s decision to send home pupils.

“If every school in the same condition as Silverdale - or worse - reacted that way, the result would be complete chaos in this city,” she said.

Many Silverdale parents and staff believe they have suffered for this long because they serve one of the city’s most affluent areas and - with 75 per cent of pupils passing higher grade GCSEs - have the best exam results in the authority. Four per cent of schools’ budgets is held back by the authority each year to help schools in disadvantaged areas. This year #163;4m was diverted for this purpose.

But of potentially greater significance is the extent to which the school has become a political football in a constituency with a Tory majority of 6,741.

In the Commons last Thursday, Prime Minister John Major blamed the state of Silverdale on Labour neglect and said it showed how the party would behave in government.

The following day the schools minister Cheryl Gillan ordered officials from her department to investigate the state of the school buildings, recently criticised in a report by the Office for Standards in Education.

Labour and Liberal Democrat councils across the country are preparing for a Tory onslaught on the way they manage their affairs in the run-up to the general election.

No one will be better primed than Sheffield, the home city of Labour’s education spokesman David Blunkett, who in the months ahead will seek to pin the blame for the country’s deteriorating building stock - which councils say will cost #163;3bn to redress - on 17 years of Conservative rule.

Jeremy Sutcliffe