Now it is a third of the way from the top. Then, vandalism was costing Pounds 40,000 a year. Last year it cost Pounds 270 for one broken window. Seven years ago, 50 pupils a year from feeder primaries were sent to other schools. Now, they all come to Garibaldi. Pupil numbers have risen from just over 500 to nearly 900. The sixth form has gone from eight students to 125. Truancy is almost non-existent, and attendance generally runs at over 98 per cent. Those are the measurable indicators.

The subjective ones - the alert, positive feel of the place and the positive attitude of all its people - are equally apparent.

How has it happened? The quick answer is that six-and-a-half years ago Bob Salisbury went in and turned the place around. But colleagues across the country want to know how he actually did it - which, presumably, is why the school’s television appearance has produced an almost unmanageable number of requests to visit.

Bob Salisbury knew early on that he would not be able to do what he wanted through the existing conventional management pyramid, made up of deputy heads with heads of faculties, years and departments. “It took three months for an idea to go down through the hierarchy and then three months for it to come back up again - and in the meantime somebody had changed their mind. The plan for records of achievement did three laps of the circuit - and this was in a school that needed massive, instant change.”

What he had to do, he decided, was to take out layers of management and replace them with something more flexible and responsive.

“We reduced the number of deputies, took out all the heads of faculties, reduced the heads of year, and got rid of all assistant heads of everything. We scrapped all formal meetings, got rid of rules for every contingency and, above all, saw the motivation and development of all staff as our greatest asset. ”

To use his own imagery, the pyramid has been replaced by a “bobbing corks” model in which, restricted only by the river banks (read “school philosophy” here) individuals are free to rise to the surface and make their unimpeded way. Implicit in this model is the idea that some of the corks will get into difficulty. He welcomes this - “I want a risk-taking culture in which inertia is the only crime.”

So far so good. But the alert reader will now want to know how motivating it might be to call in a senior faculty head, or an assistant year head, and tell her that her job has been phased out and that she has been transformed into a bobbing cork.

Here Bob Salisbury showed most conspicuously the high quality of his leadership - he interviewed colleagues and moved them on to a new way of working, positively, and with sensitive regard to status. His aim throughout was to put flesh on his belief “that we needed to release all the talents of the staff”. Faculty heads, for example, became the leaders of influential review and working groups to look at areas of the curriculum and of school life - “mini OFSTED teams”, he calls them. “They’ve done science, maths, and the pastoral system and they’re now doing art. They observe a lot of lessons, talk to a lot of pupils, a lot of staff, then come up with a kind of report that draws all that together with key issues. The report is hard-hitting and we follow up with timed targets for improvement.” (The report on humanities, which I saw, is at least as perceptive as any OFSTED document, and very clearly focused on “areas for development”.) “Ruthless promotion of talent” is how Bob Salisbury puts his way of bringing on people of ability. The present head of sixth form is a good example. “I had a teacher doing community projects. I asked him what his dream job was and he said head of sixth form. It turned out he had the clearest possible plan of how to develop a sixth form in this school, and he built it up from eight students to 120.”

Another teacher who was first doubtful and then inspired by the changes is Garibaldi’s information technology co-ordinator Sue Mackenzie. When Bob arrived, Sue had been at Garibaldi for 15 years, as an English teacher and an assistant head of house. The house job disappeared under the management re-organisation, and when she was unsuccessful in becoming a year head, she was disappointed. “I was bogged down. I couldn’t see where I was going.”

Then, in 1989, computers started to come into school. “I was interested and I began to see what computers could mean to the whole of school life.” Appraisal picked this interest up quickly. Sue found that her commitment was supported by the head and the whole team, and she became IT co-ordinator. “I had whatever training I wanted, and resources within reason. To say it’s been a new lease of life is an understatement. It was as if my teaching career started at day one again.

The word she uses most often about Bob Salisbury is “positive. There’s his perception of people’s talents, the ease of access to him, and his willingness to let you have a go and make mistakes. And if you go to see him with an idea he doesn’t want to say no. He always says, ‘let’s see how we can achieve that’.”

The effect on pupils, she believes, has been to raise both morale and expectations. “Girls especially now look beyond leaving school and having a family straight away.” In fact, Bob Salisbury deliberately aims to transmit the school’s responsive and flexible style to the pupils. “In an area like ours, where traditional industries have disappeared, pupils will need over the next 30 years to become enterprising, flexible and entrepreneurial.”

Many of the changes of the Salisbury years have cost money. There were pressing cosmetic needs at the start - to decorate rooms and replace shredded curtains. Then, more and more plans and projects needed significant cash - for computers, technology equipment, language resources, sixth-form accommodation. Here Bob Salisbury quickly showed that he is well-equipped with yet another latter-day headship skill - raising money from outside sources such as industry, trusts, the EC.

He has had to work assiduously at this. “Not a single lead came into my office. We had to go out and look for the right frog to kiss.” The accuracy of his kissing may be judged by the fact that his forays into sponsorship raised Pounds 420,000 for the school last year.

It is within our national character to look suspiciously at success, and there will be those who want to know if there is another Garibaldi tale, about snags and difficulties and trodden-upon toes, and messy resignations. Indeed, Bob Salisbury likens the first couple of years to pushing a snowball uphill. “But in the pushing of the snowball the crucial thing is keeping your head up and appearing confident.”

But after a couple of years came the kind of visible successes that win the support of doubters. “The first thing was the vandalism stopped. And gradually I was pushing the snowball on the level; then it was going downhill, gathering snow and bounding along.”