An increasing burden of decision-making now falls on headteachers and governors. They must take on fresh expertise for a bureaucratic grapple with building and health and safety regulations, local planning restrictions and Department for Education and Employment approval. All that’s before dealing with profit-driven architects and building contractors.

State schools must plan building works within DFEE guidelines. Bulletin 82, for instance, has space formulae which, roughly translated, recommend primary schools have a minimum four square metres and secondaries six square metres per pupil. The starting point for a school rethink is a head count followed by a calculation of cost per square metre.

Broadly, the choices are to refurbish or to rebuild, either with permanent or temporary structures. Net costs for buildings vary widely: the most basic of mobiles start at #163;180 per square metre; a frame building with pitched roof and brick cladding is about #163;500 per square metre; and a traditional brick building costs between #163;650 to #163;750 per square metre.

For a gross figure add 10 to 15 per cent for drainage, landscaping, car parking and so on.

A range of system builders promises low price and speedy construction. Their buildings, some of which are more temporary than others, come in standard formats complying with building rules and DFEE guidance notes. The larger firms smooth the bureaucratic hassles by selling a design-to-build service and anyone taking them on should ask for lists of previous clients and check with them that reality matches sales blurbs.

The most basic mobiles are usually erected in emergencies. The head of the Henry Maynard secondary school, Waltham Forest, praised their mobile classroom. He says: “In March our school was destroyed by fire. New temporary classrooms were acquired from the Elliott Group. Sixteen classrooms were delivered and connected to mains services within two weeks.Four weeks after the fire our school was functioning normally.”

The Elliott Group is a leader at the cheaper end of the market and has contracts with 15 county authorities to supply everything from raw rectangular huts to permanent-looking prefabs with brick cladding and pitched roofs. Some of the tiling on these has a 30-year guarantee and Elliott is quick to point out such buildings can hardly be seen as temporary.

Elliott’s most significant competitor is Terrapin. Though it still deals in factory-built structures which are assembled on-site, Terrapin sees itself as straddling the market between mobiles and permanent buildings.

A typical small-scale project was for a two-classroom brick-clad extension to St Joseph’s, an opted-out primary in Aldershot, Hampshire. It was erected in eight weeks and the deputy head, Bill James, is full of praise. “Parents, children and teachers like it. The exterior matches the brick and tile of the main buildings and there’s no indication it’s an old-style Terrapin. And no, we don’t call it a ‘mobile’. We call it ‘the new building’.”

Professor Colin Stansfield Smith would probably call it a “factory-built hut”. The former Hampshire county architect, who now splits his time between Portsmouth University and local authority consultancy work, is the enemy of all but traditional permanent structures. “We’ve always regarded any kind of temporary buildings as an excuse for poor management,” he says.“They’re wasteful of land, energy and caretaking resources.”

Hampshire has a set strategy refurbishing its schools and the Westgate secondary in Winchester is one of the professor’s examples. Roger Brooks, a Hampshire county architect, says: “We tend to work incrementally in the process of removing temporaries, refurbishing and rebuilding,” he says. Westgate has a redbrick core from 1910, huts from the Fifties and flat-roofed, modernist style Sixties and Seventies system-built blocks.

Most local authorities are too strapped for cash to provide such a coherent approach and the gap is being filled by building contractors, architects and educational facilities management consultants. Some combination of outside expertise is necessary for a traditional rebuild. It is the most expensive option though, paradoxically, can attract the greatest level of DFEE funding. That said, a rebuild takes longest, and is the most disruptive of school routine.

Victorian schools were built by municipalities that believed that standards were transmitted by bricks and mortar as well as lessons. Buildings were part of educational values, a lesson that isn’t lost on the proprietors of private schools. But schools are obliged to run as competitive cost centres and all that can be said with certainty is that Britain’s 35,000 schools face a collective repair bill estimated at #163;4 billion.

A breed of school facilities’ management consultants is emerging to bridge the building expertise gap once filled by local authority development officers. As well as co-ordinating day-to-day school maintenance, these consultants liaise with contractors.

Stephen Clyne is one such consultant and his firm, Educational Facilities Management, works for more than 30 schools at fees of about #163;1 per pupil a month. He has also sold his services on several school refurbishments in London.

His dictum is to think radically. “Stop looking at what you’ve got and think what might be,” he says. In his opinion, there’s no reason why heads and governors shouldn’t act like property developers. “Think of the asset value of your site,” he urges.

Stephen Clyne says: “Human progress has been determined by the capacity to achieve more for less.” He asks why schools shouldn’t move into empty offices and points out that cinema audiences have increased since the move to multiplexes. He suggests that schools could adopt American models where pupils rotate through premises with three weeks on and one off.

The Elliott Group, tel: 01733 52151; Terrapin, tel: 01908 270900; Educational Facilities Management, tel: 0181 424 0839