Class of 2009: Can St George's ever live down the murder of its headteacher?

Central to the Government's high-profile commitment to education over the past decade has been pouring millions into shiny, new school premises. These steel and glass temples of learning – some new-build, others lavish refurbishments of existing, run-down premises – are intended as proof positive of a determination to give youngsters a better start in life.

The cash has taken its time to trickle down to St George's Catholic Comprehensive in west London's Maida Vale, but work has finally begun on a new block of classrooms and a gym on the site of what was once the caretaker's house. When finished, it will undoubtedly lift the face that the school presents to the outside world, but for the time being, St George's peers out from behind a high, solid-black fence as an ageing collection of 1960s and 1970s buildings. In other words, it is the epitome of the sort of inner-city comprehensive disliked by education "experts", often blamed by ministers for allowing youngsters to drift into crime, labelled as part of "broken Britain" by the Tories, and shunned with horror by every aspiring middle-class parent.

St George's also carries the additional burden of national notoriety. Outside the main gate, where on a sunny autumn morning groups of 11- to 16-year-olds are starting to arrive, is a plaque that commemorates headteacher Philip Lawrence, who was stabbed to death here in December 1995. (Lawrence was killed when he attempted to stop an attack on a pupil of St George's; 15-year-old Learco Chindamo, who didn't attend the school, was convicted of the murder.) The shadow of that much-reported tragedy has hung heavy over St George's ever since. "The only thing I knew about the school when my mum told me I was coming here," says 12-year-old Ali, not even alive in 1995, "was that it was where the head had been murdered. It made me not want to come."

Now Ali knows what actually goes on behind the school gates, however, he says he wouldn't want to be anywhere else. Fourteen turbulent years after Lawrence's death, St George's finally seems to be living down its past. It has been a struggle. It was closed for two weeks in March 2000 "to ensure the safety of pupils" after gang fights broke out in classrooms. A new head, Marie Stubbs, was brought out of retirement and when, 18 months later, Ofsted gave the school a favourable report, she trumpeted her claims to have turned it around – first in a memoir and later in a prime-time TV drama starring Julie Walters. But Stubbs left in August 2001, and by 2005 standards had fallen so low again – "I lasted three days before walking out," recalls a member of staff from that time, "during which I was threatened with stabbing for daring to challenge a Year 11 boy for smashing a ball out of my hands during class" – that closure seemed inevitable. '

As a final throw of the dice before renaming and rebuilding, possibly as an academy, a new head was appointed. Martin Tissot already had form in resuscitating a stricken inner-city school in south-east London without recourse to costly gimmicks – and Tissot claims that, when he arrived in September 2006, St George's had one of the biggest budget deficits of any school in the country. Further to that, when he took up the post, just 30 per cent of pupils were reaching the Government's basic expectation of five A to C passes at GCSE. By this summer, that figure had risen to 88 per cent, without any significant change in the backgrounds of the children who come here.

This is a school where more than half the intake has English as a second language, 50 per cent are on the special- needs register, 40 per cent have free school meals, and pupil turnover, because of often chaotic family circumstances, is high. Yet, despite a list of challenges that have defeated many other inner-city comprehensives, St George's has gone from the bottom to the top of most league tables when it comes to measuring "value added".

Its is a remarkable story, and one that poses some intriguing questions in the education debate, especially in these straitened times, about the value of costly makeovers and flagship Government policies as against a reinvigorated commitment to the basics – decent classroom teaching and strong leadership. And, for a society struggling to formulate a response to the manifestations of alienated youngsters – gangs, knife crime and record numbers in juvenile courts – St George's offers a new take on that familiar Blairite slogan of education, education, education.

It's just before nine o'clock and the last stragglers are hurrying through the gate before it closes to join their 600 St George's schoolmates already lining up in an orderly fashion. One of Tissot's first acts as incoming head was to insist on a strict uniform code – black blazers and proper black shoes for all, no make-up or jewellery for girls, no bandanas or bands with gang colours for boys, and (a more recent innovation) clip-on ties that cannot be sculpted into rebelliously thick stumps, and which have the additional benefit of requiring the collar button of the regulation white school shirt to be done up to accommodate them.

As the playground racket ebbs away so that only the traffic on the busy A41 beyond the boundary fences can be heard, Tissot, himself the father of two primary-school age children, stands at the front, his piercing blue eyes scanning the columns of pupils for uniform code-breakers. He is, it should be said at once, not your regimental sergeant-major type of headteacher. Slight in stature, he possesses instead a natural presence and authority that requires no buttressing by a puffed-out chest, academic gown or loud growl.

As a line snakes past, he pulls out a young Asian boy whose white shirt is hanging out at the front. "Tuck it in, Ray," he tells him. The tone is firm, ever so slightly weary at having to repeat himself, but not intimidating or degrading. Ray does it at once. One of the senior staff, head of geography Andrew Wheeler, labels the approach to discipline at St George's as "modern strict". Another, John Asgian, is keen to point out that it is not zero tolerance. "That implies zero judgement and that is not what we are about."

"Uniform is to do with pride," Tissot explains. "We are in business and I want us to be more business-like and proud of what we do and achieve here. You have to find ways of levering up expectations." It wasn't, he admits, a message readily embraced by pupils when he arrived. Dillon, now a tall, baby-faced 15-year-old, was just starting out in Year Eight when the new head turned up with his new rules. "St George's back then was a place where there was no need to be good because when you were bad, there was no comeback. I used to get into fights all the time and nothing ever happened to me."

Dillon doesn't appear to have even a whiff of nostalgia for this period, when the pupils were evidently running the place. "At first, when Mr Tissot came, I did think, 'I'm not going to wear a blazer or give up my trainers,' but now he's made me realise we aren't here to mess around. We are here to work, and we need to dress for work." '

The pupils heading off to their classrooms in St George's' two main blocks are fairly evenly divided between boys and girls. Some of the latter wear Islamic headscarves. Once, the school's intake was homogenous and reflected the high number of Irish immigrant families in a local catchment area that was referred to affectionately as County Kilburn. Today, though still Catholic in name and ethos, the school embraces the whole range of ethnic and religious backgrounds that make up a multicultural capital city.

"I grew up in the 1960s in Cricklewood, just north of here," recalls Tissot, "and St George's was one possibility my parents discussed as a school for me, but back then it had a reputation for being a bit rough, so I went elsewhere." Rough is a word that is still routinely used in connection with some of the neighbourhood council estates. Their high proportion of hard-to-let properties means they are often the first port of call for refugee families, asylum seekers or those in trouble. And so, for their children, is St George's.

Because of its well-publicised troubles, the school suffered from falling rolls for many years and so always had places to spare for children who often spoke no English and had missed out on large chunks of their education. As doubts increased about its future, St George's became a dumping ground for pupils other schools didn't want. "We are still not a school of first choice for many parents," acknowledges Tony Kilgallon, head of inclusion, "though that is changing as our results improve. This year, we were oversubscribed for the first time. And it is certainly true that we attract a large number of pupils who have only arrived in the country recently, and whose parents often will have had minimal contact themselves with education."

Yet – unlike five years ago – St George's can now hold up success stories. Aldi Kolnikaj came in 2006 from Kosovo with only a smattering of English. This summer, he notched up 15 GCSEs, including As in English literature, additional science and business studies. His classmate, Amaka Nwagbo, was a recent arrival from Nigeria when her family sent her to St George's. "They didn't understand schools here," she says by way of explanation. Of the 14 passes she has just got at GCSE, four were A-stars and seven were As. She is now studying for A-levels at a sought-after grammar school in Finchley (St George's has no sixth form) and plans to study medicine.

Up on the top corridor, Faye Tolson is taking a Year Seven group for their morning session of ICT (information and communications technology). All is calm as each child sits at a computer terminal. In the spirit of modern strict, Tolson allows a low hum of noise. It is relaxed but unmistakably controlled as Tolson, young, blonde and engaging, explains that she first came to St George's on the Government's "Teach First" scheme. This takes recent university graduates (including, in the past, Nicky Blair, son of the former prime minister) and, after an intensive six-week training course, parachutes them into the classrooms of what it coyly terms "challenging" secondary schools. The theory seems to be that the new blood will give these institutions a shot in the arm, the young and keen inspiring the even younger and disillusioned. If the recruits survive and flourish after a year on the front line, they gain the equivalent status of a newly qualified teacher.

There are a number of Teach First-ers who have come to St George's and stayed since Tissot took over. He is frank in admitting that one attraction for him in recruiting them is that their wage cost is inexpensive but, more crucial, he stresses, has been their capacity to inject energy and enthusiasm not just into pupils but also into a staffroom where uncertainty about the future had taken its toll on morale.

"Martin likes fresh, enthusiastic young teachers," confirms Jennifer Cornish, head of special needs. She was already in the post when he arrived. (Most staff I meet immediately define themselves as Before or After Tissot.) "Their presence," she goes on, "has been great for the rest of us. It's infectious. You can't help but feel more enthusiastic about what you're doing. It's made me a better teacher."

So are the young teachers in this hitherto troubled school idealists, I ask Lindsay Loftus, a twentysomething who grew up in France, came here on a training placement two years ago, and is now head of maths. Floating somewhere in the back of my mind as I pose the question is Sidney Poitier in To Sir, With Love. Loftus, though, brings me back to earth. "I suppose that's one way of describing it," she replies, "but it's quite selfish really. As a teacher you want to make a positive difference and here at St George's, while you don't with every pupil, you feel as if you are making a difference every day."

As well as their classroom duties, the staff run a burgeoning programme of after-school classes, excursions and overseas trips. Tolson, for instance, describes getting her business-studies pupils to stage their own version of The Apprentice. "It worked really well," she enthuses. "We set them a series of challenges. One was to go to the traders on Kilburn High Road and bargain with them. You'd be amazed what they came back with."

Joseph, from Year 10, came second in the competition. I bump into him later, in Tissot's office, as he is trying to explain why he has got two Xs in his school diary (another innovation has been the behaviour code – an X each ' time you misbehave, with two in a week bringing an after-school detention, and three a Saturday-morning punishment). Year 10, several of the staff suggest, is the trickiest in the school, because it was the intake that came when it seemed inevitable the school would close. Theirs was hardly a positive choice to come here, and some have been among the hardest pupils to enthuse about the new way of doing things here.

But Joseph's face lights up when I ask him about The Apprentice. It may, of course, be relief at deflecting the conversation from the head's grilling, but his enthusiasm is unmistakable. "It was all about confidence," he says, "and not being shy and seeing things as a possibility. It made me realise that life was too short for messing about." There is perhaps still a gap between realising and acting on it.

For those whose Xs pile up and who are persistently disruptive or truanting, there is the Learning Support Unit behind the main school. Again, the outward appearance couldn't be bleaker – black gates with padlocks, and behind them a series of portable classrooms. "Why would we want to make it look attractive?" Tissot points out as he takes me over.

As he walks, he is constantly – and apparently unconsciously – dipping down to pick up stray bits of litter in the corridors. While he is clearly not someone who thinks the answer to a troubled school is to knock it down and build something shiny and new, he does believe that order and a professional appearance extends beyond pupils and staff.

"Exclusions," he explains as he walks, "were extremely high when I first came here but that was because the behaviour was so bad. I was putting down a marker. It didn't cause me any difficulties, but there were a few raised eyebrows at the local-authority end." That initial period of setting and enforcing new boundaries has now passed. "I exclude very few pupils now," he continues. "And to permanently exclude is, I believe, an admission of failure on our part."

Earlier, he had showed me a table, pinned to his study wall, that lists bad behaviour and, alongside, in black and white, the punishment it will incur. "It is important to be clear and consistent. The only thing I would exclude for is persistent bullying. That has no place in any school."

As numbers of exclusions have dropped, so too have those sent to the Learning Support Unit, according to its head, Marlon Robinson. "Four years ago, when I arrived [Tissot brought a number of the senior staff with him from his previous school], we regularly had 35 in here. Now it is more often 15 or 18 and they don't want to be here. They want to be in mainstream with their mates. They know enough about St George's now to know they are missing something being here."

While they are sent here as a punishment, the regime in the unit is not part of that punishment. Quite the opposite. Pupil-to-teacher ratios are high. Ennis, 14, is being helped with a maths paper. Why is he here? "To be honest, I don't know," he replies and lapses into silence. It is, I conclude, bad enough to be in the Learning Support Unit without finding yourself being interviewed by a journalist as well. Suddenly, he pipes up again. "But I'm going to make sure it's only today."

It transpires that he should be on a work placement but has refused to go. Next to him is Kevin from Year 11. "I haven't been in here since Year 8 when I used to fight a lot," he admits, "but I got in a fight." Does he feel he is being unfairly punished? For a moment he looks at me blankly before replying, in a puzzled tone, "No." If they have been planted to give me the right answers, Tissot is even better organised than he appears.

It takes only half an hour of being inside St George's to realise that the view from the outside of this being the "Philip Lawrence school" is way out of date. Yet after a whole day of working my way around calm, tidy corridors, watching lessons and talking to staff and pupils, I'm still struggling to pinpoint why the place is now thriving when so recently it was imploding. It is when I spot Martin Tissot, out in the playground at going-home time, having a quiet chat with a boy whose top button is undone, that I realise my mistake is looking for the "big idea", as politicians are prone to doing in education – whether it be new buildings, new private investment or new mechanisms of parental choice. St George's is doing well thanks to a package of powerful ideas, none of which is new, and none of which costs a fortune – namely, strong leadership, commitment, discipline, team effort and enthusiasm, and a culture that celebrates achievement. These ideas are all so familiar that some are now unfashionable, but here they are working triumphantly to provide youngsters who often have little other support in their lives with opportunities.

The closest I get here to a catchphrase is in conversation with John Asgian, a New Yorker who spent 25 years in the City before deciding to retrain as a teacher and coming to St George's. "Insistency, persistency and consistency, that's our formula. Or, as my Irish grandmother would have put it, being a nag."