The window is broken, a strip light hangs halfway off its mounting and chunks of plaster have been knocked out of the grey painted wall. A doorway is blocked off with graffiti-covered chipboard and the dull brown linoleum floor is dotted with trodden-in chewing gum.
"There is a toilet and you can imagine what that's like," warns Bailey Wood, 11, who is showing me around Reddish Vale Technology College. We decide not to go in.
Pupils and staff agree a single word sums up the state of their changing rooms: "minging". But because this secondary in Reddish, Stockport, became the country's first co-operative trust school last April, help may soon be at hand.
Being a co-operative is different from standard trust school status. It means pupils, staff and local community - rather than a business or other external body - form a charitable trust with a say in how the school is run.
It has echoes of the first ever co-operative formed 15 miles down the road in Rochdale 150 years ago when the town's weavers and other artisans opened a shop to sell their goods (see panel, overpage).
The idea is being backed by both leading political parties. Despite the co-operative movement's long association with Labour, it was David Cameron who first showed support. In November 2007, the Tory leader praised Reddish Vale's plans to create a co-operative trust and said he wanted to "create a new generation of such schools in Britain, funded by the taxpayer but owned by parents and the local community".
Ed Balls, the Schools Secretary, responded in September 2008, saying he wanted 100 schools to follow Reddish Vale's example and pilot the co-operative trust model.
Like the Tories, Mr Balls - one of 29 Labour MPs who are also members of the Co-operative Party - chose to emphasise the greater role it could give parents in schools.
But at Reddish Vale it has been pupils, rather than parents, who have made the early running. So far 250 (about a fifth) are members of the trust, as are 15 or so parents and 30 to 40 of the 150 staff.
"We have gone for learners first of all because they are interested in changing their school," says Phil Arnold, the deputy head.
Their first priority has been to sort out the changing rooms, which is where the practical benefits of forming a trust have been seen. As well as drawing pupils, parents and the wider community into the school and giving them some authority through two seats on the governing body, the trust can act as a financial body, independent of the school. This allows it to bid for public funds that the school would not have been able to access.
The comprehensive was built in 1952, so the buildings are showing their age. Sections have been refurbished as and when money became available. This make-do-and-mend policy is showing its limitations and Stockport authority is near the back of the queue for money from Building Schools for the Future.
"It's not that we are a horrid school and don't look after pupils in their changing rooms," says Jenny Campbell, the head. "It's that the condition is so bad that, without half a million pounds, there is no point doing it."
In the spirit of co-operative self-help, pupils have produced their own plan to develop facilities into a new sports and community centre, to be run by the trust for the local community. They will learn early this year whether their bid for Pounds 8 million from the myplace scheme run by the Department for Children, Schools and Families has been successful.
The idea has already started to capture pupils' imaginations. Ms Campbell expects that the closer to reality it gets, the more people will get involved in the trust. She hopes it will grow organically, gradually involving the wider community and allowing former pupils still living locally to retain links with the school.
Trust membership is strictly voluntary, but co-operative values such as self-responsibility, democracy and solidarity are being embedded into the curriculum and taught to all pupils.
"I still don't think many pupils know about it," says Jessica Pike, 14. "The pupils who do know, I don't think they know enough about how to take part. But it brings a stronger pupil-teacher relationship, and if more people get involved, we will have a greater respect for each other."
A formal structure has been set up, with trust members feeding into forums of pupils, parents, staff and the community. These forums are represented by trustees, two of whom are governors. External partners include a further education college, a local entrepreneur, the Co-operative Group and Manchester Metropolitan University.
But in reality it has been working in a more informal, consensual way, with little need for votes. Pupils and staff have also started to use the trust as a more direct channel to suggest new ideas.
Their imaginative plans for the community centre bid include a radio station, boxing gym, aerobics and dance studio, offices for police and youth services and an advice and guidance centre run by young people for young people.
Mr Arnold talks enthusiastically about long-term plans to create a business centre for social enterprises and develop a nearby park into an environmental centre.
Staff had initial reservations because the move from direct local authority control to trust school might have threatened job security and pay. But there is now a belief that it could actually protect support staff who might have been vulnerable to local authority cutbacks.
"There is more of a community," says Lucy Cordingley, a trust member and drama teacher. "We are all in it together."
Carl Carter, a history teacher, says communication between different departments in the 1,320-pupil school has already improved, but he believes the trust is far from realising its full potential: "It may take 5 to 10 years," he says.
Reddish Vale had already made links with the wider community in its four years as a full-service extended school. Local primaries, youth community groups, small businesses and nearby residents have all used the school's facilities, which have been open from 7.30am to 11.30pm for 51 weeks a year.
When Tony Blair's trust school reforms were introduced, the school saw the opportunity to take this process a step further.
The trust school policy was dreamt up in 2005 as a way of introducing greater choice and diversity in the state system and opening it up to new ideas. It allows businesses and other external organisations to gain influence over schools in a much quicker, cheaper and less cumbersome way than academies can - so long as governors agree.
Reddish Vale decided to adapt the policy so that the trust became a membership organisation. "We thought if we could offer people a share in the trust - instead of using, if you like, a plc model, where the great and the good come in - we thought it would encourage greater engagement," says Mr Arnold. "It didn't take long before somebody pointed out that this was actually called a co-operative. I think we had invented co-operatives about 150 years too late."
Having realised the historical context of what it was doing, Reddish Vale has become a fully fledged member of the co-operative movement. Last month, pupils and staff attended a conference of similar "mutual" organisations, rubbing shoulders with the likes of the John Lewis Partnership, the remaining mutual building societies, the Co-operative Group and NHS hospital trusts.
"A lot of co-operatives are still embedded in the communities around here, but it is almost as if a veil has been pulled over them," says Mr Arnold. "My generation and this generation have maybe lost touch with why they are there, why they are different.
"We are tugging at that veil and trying to go back to those original Rochdale Pioneers. Their values have stood up over 150 years, so we thought, 'Why don't we use them to develop what we want in the community?' They are what we believe in anyway."
- In 1844, the Rochdale Society of Equitable Pioneers was set up by 28 weavers and other artisans. They opened a store, owned by community members, and became the world's first co-operative.
- There are now 16,485 co-operative or mutual organisations in the UK, with 23 million members, 844,000 employers and assets of Pounds 477bn.
- Co-operative schools already exist internationally, in Spain, Sweden and Canada.
- Reddish Vale Technology College became the first British school to join the movement last April, with another 100 expected to follow.