Mervyn Wilson is feeling bullish about the snowballing progress of the fastest-growing schools network in England. "It's a quiet revolution," he says. "By next year, we expect there to be well over 200 schools, with the potential of that growing substantially in the next few years."

Those following the development of our rapidly changing education landscape could be forgiven for guessing that Wilson works for one of England's high-profile academy chains, which are often mentioned in ministerial speeches and seem very well connected at the Department for Education.

In fact, Wilson is chief executive of the Co-operative College, a Manchester-based organisation that is helping to support and promote what he says is the ground-up, democratically driven growth of Co-operative trust schools. These are part of the Co-operative movement, with a history dating back to the 19th century.

Almost unnoticed, Co-ops are thought to have increased in number so they now make up the third largest association of schools in England, after those run by the Church of England and by the Roman Catholic church. They easily outstrip more publicised groups such as Ark Schools or the Harris academy chain.

Wilson likens their development to community-run village shops, or to Supporters Direct, which campaigns for football clubs to be run by fans.

Reddish Vale in Stockport was the first school to become a Co-operative trust, less than four years ago, but there are already 151 Co-op schools across the country, with numbers having trebled in just over a year.

In Cornwall alone, Wilson says, 70 to 100 schools will have joined Co-operative trusts by the end of this year, making a total of well over 200 nationwide by early in 2012. Nine primary schools in Burton-on-Trent, Staffordshire, are already part of a joint trust, with another eight about to consult on joining. South Yorkshire, with approximately 50 schools expected by 2012, is another area of strength for the movement.

So what are Co-operative trusts, and why are the numbers growing? The Co-operative movement itself dates to the early 19th century – although some argue it goes further back – and the ideas of the cotton magnate Robert Owen.

The principles were that people would come together to form membership organisations based on common ownership or mutualism. In 1844, the Rochdale Society of Equitable Pioneers was established by 28 workers in the Lancashire town, quickly growing and forming the model for the modern Co-op group, which includes businesses from the well-known supermarkets to travel insurance, funeral services and banking.

The Co-operative movement also set up schools in the 19th century, including one established by the Rochdale Pioneers themselves. But Wilson told a conference last month that the idea of Co-operative involvement in schools had gone out of fashion by the 1980s.

This began to change five years ago, following one of the most intensely contested pieces of legislation piloted through parliament by Tony Blair: the 2006 Education and Inspections Act.

This established trust schools, billed as "independent state schools", which were to be set up with weaker links to local authorities than conventional state-funded institutions, and which would be run by a trust that could include businesses, charities, faith groups and universities. Each had to have a parents' council that would have a say in the school's day-to-day affairs.

Of the more than 500 trust schools in England, Co-operative trusts are now believed to be the largest grouping. Distinctively, each school allows pupils, teachers, parents, local people and employers to become "members" of the trust, forming a "community-based mutual" organisation.

The members elect representatives to a "stakeholder forum", which then expresses the views of the wider group to the school leadership, while also electing trustees, who in turn elect some of the members of the school's governing body.

Typically, several Co-operative schools are linked together in a single trust: often a group of local primary schools working with a secondary.

There are also now three Co-operative academies, where formal links with the local authority are even more minimal than in the case of trusts.

All of this seems to fit well with what many within the Co-operative movement view as core educational values: democracy, equity and fairness.

It has also played well with politicians from both major parties, with David Cameron strongly endorsing Co-operative schools as opposition leader in 2007 and Ed Balls, as schools secretary, pledging in 2008 that 100 would open by 2010.

But there appear to be other factors behind the rising numbers. With the role of local authorities growing more uncertain, schools are looking for new ways of sharing expertise. Co-operative trusts, or even Co-operative academies, are seen by some schools as alternatives either to going it alone as a single academy or to joining a large sponsored academy chain, says Wilson. The reasons for taking the Co-operative route sometimes seem practical, and sometimes philosophical.

In Cornwall, schools have been encouraged by their local authority to form collaborative arrangements in order to pool resources.

Although the government hopes that eventually all schools will be academies, a paper, Championing Children, Championing Excellence, produced by Cornwall council in April said that small primary schools in particular would find it difficult to take on the extra responsibilities of academy status, including land, staffing and purchasing decisions while remaining financially viable. "The local authority does not believe that any single small primary school can be effectively sustainable into the future … as an academy", said the paper, because of the extra management overheads autonomous academies would bring.

Although Co-op schools were not mentioned in the paper, they seem a natural alternative, because schools can band together to share expertise and jointly buy in services. Six groups of schools are therefore joining Co-ops in the county.

Most provocatively for Wilson and some heads now running Co-op schools, the movement also rejects what it sees as a developing "semi-privatised" education system, with academy "brands" competing in a market structure underpinned by the values of corporate business.

It contrasts what it sees as the democracy of the Co-operative movement, with schools networking in groups and each institution interacting with its stakeholders, with conventional sponsored academy arrangements, which allow private sponsors to appoint the majority of each school's governing body, and where academies are often closely supervised from head office.

However, academy chains are also growing. Ark Schools was set up in 2004 by the hedge fund manager Arpad Busson, and now has 14 academies either open or in development. The Harris Federation, sponsored by Lord Harris of Peckham, chairman and chief executive of the retailer Carpetright, runs 13 academies in south London, with plans for another 12.

E-ACT, a charity run along business lines by the former Labour government's schools commissioner Sir Bruce Liddington, operates 11 academies and reportedly hopes to run 250 schools within five years.

All of this underscores the need for a Co-op alternative, says Wilson. "The break-up of local authorities and the development of these chains needs to be viewed as the latest phase in the marketisation of the education system," he told a Centre for Successful Schools conference at Keele University last month. "There are many of us who now feel that there is not just space, but a desperate need, for a community-based alternative."

Steve Baker is head of Lipson community college in Plymouth, which is in a Co-operative trust with six primary schools, and which embodies the movement's ethos. It has 200 members, the school runs pupil drama and choral groups on a co-operative basis, and even has children work together "co-operatively" in small groups in lessons.

Baker says: "Philosophically, we could not be further opposed to the top-down academy chain model. Education is very precious. It's much too precious simply to hand over to philanthropist sponsors. We had that model in the 19th century. We've come a long way from that."

Robert Owen was himself a 19th-century philanthropist, so there are ironies here. And academy chains obviously take a different view.

David Wootton, chair of the Independent Academies Association, says: "The academy movement, and sponsored academies in particular, have a strong commitment to social justice and moral purpose. This means a dedication to the communities they serve and a deep desire to improve outcomes and "close the gap" for students in some of the most challenged communities. Many academies have very strong community routes.

"We in the academy movement welcome the support of the Co-operative movement, who are now actively involved supporting academies, and believe there is room for a diversity of providers."

Despite their democratic appeal, trust schools in general are viewed by some campaigners for conventional state education as a form of privatisation, and some might view the Co-operative movement cautiously, as yet another interest group seeking influence in schools.

However, this is a significant movement, and is likely to have a say in the future of English education for a while to come.