Top of the class in architecture

With their brick façades, faceless classrooms and endless corridors, schools are boring, aren't they? Not any more. Jay Merrick visits two new primary schools that inspire as well as instruct

Two brand new schools – one in central London, the other in Kent – demonstrate quite beautifully what happens when good architecture and the kind of ambition that hovers right on the edge of risk-taking come together in a dynamic way. Both schools are, in very different ways, showstoppers. But their key virtue is not their pizzazz. It's that they have maximised site potential – and learning environments – to an extraordinary extent.

Two brand new schools – one in central London, the other in Kent – demonstrate quite beautifully what happens when good architecture and the kind of ambition that hovers right on the edge of risk-taking come together in a dynamic way. Both schools are, in very different ways, showstoppers. But their key virtue is not their pizzazz. It's that they have maximised site potential – and learning environments – to an extraordinary extent.

Sevenoaks is very much Soft South, a wealthy town characterised by herds of 4x4s, trolley-pique in Waitrose, and fresh-faced lads with bogus glottal-stops trying hard to "reprazent" the Oaks Massive. The town is also conveniently near the M25 and about 35 minutes by train to Charing Cross in central London; it's an essentially orderly, middle-class place that can boast at least two excellent primary schools, a public school and access to grammar schools in nearby Tonbridge. Sorted for ease and whizz-kids, you might say.

Earlier this year, on a site on the south-western edge of Sevenoaks at Riverhead, I noticed several large tubular arches been set, in a spaced-out row, into reinforced concrete pads. These anchors were, in turn, tied into rather expansive foundations. It was easy to imagine the ultimate general form of the building. It had to be some kind of superstore.

As the months passed, the tubular beams were given coats of paint; and the main mass of the building rose under them, interrupted by two mysteriously projecting blocks, one painted red, the other blue – and in distinctly bright shades, at that. It was not, after all, going to be a superstore. But what else could it be?

It was only when the gently curved roof covering was put on that the penny dropped. The obvious materials to use were aluminium, zinc alloy or copper. What appeared were mats of vegetation – sedum, to be precise, a robust semi-succulent plant used in a well-established "green" German roof-covering system. This was the giveaway. It was going to be a school, and architecturally notable. Not quite great architecture, mind, but an excellent architectural solution. Here was a building raised under the auspices of Kent County Council and built to state education per-square-metre costs – yet it looked like something that only Bedales or Millfield could have afforded. Furthermore, it was a mere infant school.

What a difference to the original, red-brick Victorian school it replaced. And by Sevenoaks' standards of standardness, what a nerve! But the school is delightful and its designers, Architects Design Partnership, are to be congratulated. So, too, are the school governors, led by Jenna Leight, who picked this relatively outlandish solution from a shortlist of designs thrown up by the architectural competition they set up. Here is a school whose form is locally unique and whose internal organisation has delivered airy, naturally-lit classrooms looking out over its very own field of dreams.

Not an off-the-peg school, then. And it had another key advantage: a large site that sloped away from the A25, a site manipulated gracefully by landscapers, Rummey Design Associates. Rummey has given the children an expansive, gently undulating mixture of grassy knolls and a purpose-built play area. From here, the building rises in empathy with the land. ADP's building is simple enough, but they have scaled its mass and details very effectively. It is strange – and strangely charming.

Not charming enough, for some. The parish council loved it; so, too, did the planners and chief executive of Sevenoaks District Council. Their enthusiasm was vital in successfully countering Kent County Council's reservations that the design was too outré. KCC had a right to be fearful: it was spending £2.38m on the school, and committing a further £1m from the Government's now shelved New Deal For Schools budget.

There are, predictably, people in Sevenoaks who think the school is a horror. Jenna Leight admits that "a lot of people think it's wonderful. Some think it's awful – and why on earth did we have those bright colours?"

Because children like them, obviously. They also like surprises. And what could be more surprising than Building Design Partnership's superb, sail-topped Hampden Gurney Church of England primary school, half a spit off London's Edgware Road?

It is no surprise that this glassy bulge in Nutford Place, about 300 metres north of Hyde Park Corner, has been shortlisted for the Stirling Prize. But, like Riverhead Infants School, it is surprising that it is there at all. On a site hemmed in by apartments (this was once middle-class, Leslie Phillips lounge-lizard land) and a medium-rise Marriott hotel, not to mention a cauldron of energetic businesses and eateries catering for Middle-Eastern tastes, Hampden Gurney school presents glass, glass and more glass, rising and regressing for five floors like the rounded end of a wedge of cheddar.

On four of those floors, the glass is not there to act as windows but as high screens to keep most of the wind and rain off semi-circular play decks that are coated with a recycled rubber finish. From these decks, children can look down on the Safa restaurant and a Coffee Republic outlet in Nutford Place or, on the higher levels, the skyline of London W1. The classrooms are positioned at the sharp end of the building, which overhangs the basement-level play area so that part of it can be used even if it rains.

The design, for all its façade drama at street level, is essentially very simple. And, for the most part, BDP has carried off the details pretty well. Some problems will remain, though. The shape of the playground's high retaining walls amplify and muddy the shrieks and yells of the children: the architect's attempt to attenuate this dilemma with patches of textured bricks is plainly not enough. And, while the use of glass is generally excellent, the school cannot yet afford to pay costly abseiling window-cleaners.

No matter. BDP has done a fine job for a so-called "beacon" school – a school whose children, very shortly after taking possession of it, were plainly blasé about their delightful surroundings. Something must be right, then. Despite its pristine newness, the school feels as much a part of the locale as the Meshwar café, KK Electronics, the Shazia Food Hall and La Femme Elegante just round the corner in Edgware Road.

Why can't more schools – particularly those in cramped urban areas – be like this? Answer: a bureaucratically anal attachment to the status quo and a fear of architects who propose anything that demands, and provokes, imagination.