When members of Parliament talk about “the other place”, they are referring to the House of Lords. But when headteacher Philip Snell refers to his “other place”, it could be either Kingsbury or Willesden high schools, depending on which desk he has his feet under at the time. “I take the chip out of my brain when I cross the north circular,” he says, describing how he copes with his role as the head of two schools.

In the struggle to find effective ways of intervening in troubled schools, some education authorities are borrowing heads of successful schools to troubleshoot in their failing neighbours. Which is why Philip Snell has temporarily abandoned his polished wooden desk in a trophy-studded office at Kingsbury for an eyrie at the top of Willesden high, where damp stains the woodchip paper above the windows and a can of insect spray is the only ornament. If the office at Kingsbury feels like the domain of a successful chief executive, the one at Willesden resembles the field headquarters of a military operation - a whiteboard, crammed with points under the heading “Key Issues Following HMI Inspection”, dominates one wall.

Willesden and Kingsbury are both in the London borough of Brent, and both have a high proportion of pupils with English as a second language. Other than that, they have little in common. Willesden high, in special measures for the past two years, is in the south of the borough. In the early Seventies it had nearly 2,000 pupils, but by the time Philip Snell was drafted in at the end of last year, numbers had fallen to around 400 - with a budget deficit to match. Closure loomed.

Kingsbury, on the other side of London’s ferocious north circular road, is in the more prosperous part of the borough near Wembley and known by some as the “green fields of the north”. A foundation school, it has a large and thriving sixth-form, selects 15 per cent of its Year 7 intake, and this summer, with 800 families competing for the 300 places on offer, expects to hear more than 100 admissions appeals.

Late last year, with the departure of Willesden’s then head imminent, Philip Snell was asked by the local education authority to come in, first as a consultant, then as acting head. They wanted the troubled school to begin not a “fresh” start, he says, but a new one. He cleared it with his governors at Kingsbury - “they had to be persuaded it wouldn’t affect the other school” - and accepted.

“It was a challenge,” he says. “I also care about the life chances of children.” Formerly a civil servant at the Foreign Office and the Treasury, Philip Snell went into teaching because he “didn’t want to wear a grey suit and be an administrator”.

Now he spends most of his working week at Willesden, where the head’s job is a very different proposition from the one he is used to. Much of the time is spent listening to students. Early on the day of the TES visit, a pupil on report arrives to check in with the head. He’s late, he says, because he had to go to speak to the head of his eight-year-old brother’s primary school about bullying - mum doesn’t have enough English to do it. “Keep up the good work,” says Philip Snell, perching on the corner of the desk. Shortly afterwards another pupil arrives with a long and convoluted explanation about a missing mobile phone. Twenty minutes in, a kitchen knife and some older brothers enter the story. Philip Snell takes careful notes, sighing softly. He brightens up with the next visitors, three GNVQ business studies students who have won an award for their business plans.

He is undoubtedly a good listener, but on a larger scale what can a head who is part caretaker and part troubleshooter actually do? For Philip Snell and long-time colleague David King - brought into the school at the same time on secondment from the Brent LEA’s finance department - the black hole that was the school budget presented itself as top priority. Between November and January, the school recruited almost 250 students, most of them Kosovan refugees. “We spoke with the staff, and encouraged them to accept that I was going to bring in a lot of new students,” says Philip Snell. “It enabled us to tackle the budget deficit and provided stability, because Years 10 and 11 are now full.” A predicted deficit for 19992000 of pound;233,000 has been narrowed to pound;60,000. Three Albanian-speaking support staff have been recruited, two of them teachers.

Another pressing part of the head’s task here is to begin turning around Willesden’s poor reputation. “You’ve got to persuade politicians, the DfEE, the local population and children themselves of the value of this exercise,” says Mr Snell. “It’s fraught with difficulty. Certain things have to happen over 18 months rather than six.” PR has been one step forward, two steps back, he says. A positive write-up in a management magazine was undone by negative local headlines after an excluded pupil attacked another in the street.

Were staff willing to believe he had something to offer the Cinderella school of the borough, coming from the flagship? “I had to win friends, certainly,” he says. But after 30 years in the borough, he knew some of the staff personally. He describes his approach as “open but unequivocal”. He says:“I had to tell staff bluntly that if we didn’t take in the new pupils, the school would have to close.”

At the same time as trying to establish basic good practice, as acting head he has to leave plenty of scope for his permanent successor, who arrives in September - which may explain why Mr Snell jokes that he has moved from “white knight to lame duck” in five months. “What’s needed is space and time to develop a strategy for a development programme over a period of years,” he says.

Spending a day with Philip Snell, it is obvious that Willesden has entered his heart. He speaks with mournful affection about the staff and children there, about the “stupidity” of league tables and the need to make staff feel “pleased with themselves”. He says:“I believe in people. I genuinely believe people make the difference.” Proof might be that he is taking only petrol money for what he does here, although he retains his salary as Kingsbury’s head.

When new head Frank Thomas, from the Ralph Allen school in Bath, takes up his post, Philip Snell will return to Kingsbury, but he will retain a support role at Willesden. “If they can pull in the children who live in the area, they can have the same constituency we have. People talk about social issues, but there are social issues at all schools in the borough.”

His time at Willesden has taken its toll “in the form of tiredness, my social life, whatever it was”. He admits to difficult days at Willesden, when he has gone home wondering what to do about situations. But the head’s job is to cope, he says. “You can’t appear to be stressed. You’ve always got to appear able to maintain your equanimity.” It has also warded off “conceit, the headteacher’s disease”.

Meanwhile, how is Kingsbury faring in his absence, under the stewardship of first deputy head Clem Chung? On a walkabout, Philip Snell notices clematis unplanted in one of the garden areas; a pupil seems miffed that he didn’t attend her recital and barbed jokes in the canteen suggest he is missed. Have staff and students there felt abandoned? “People would like to see me more,” he says. “But the school is running well without me. Some staff and parents became apprehensive because they thought I had left, although I made clear from the beginning that my commitment was for no longer than six months.”

Marsha Elms, head of Kendrick school in Reading - a high-performing foundation schools for girls - says six months is the longest any head can afford, practically and emotionally, to be engaged elsewhere. She should know: in the summer term of 1998 she took on the job of acting head of Ashmead School in Reading, after “a phone call out of the blue” from the chief education officer. “The time limit was one or two terms maximum,” she says. “I felt instinctively I would lose touch with the school if I did it for longer, and that was something that did almost start to happen, because the new school took such enormous energy.”

The contrast between the two schools could not have been more marked. While Kendrick had got 100 per cent of its pupils through with five GCSE A-C grades the previous summer, Ashmead had managed only 6 per cent. “The school was in enormous difficulties,” says Marsha Elms. “There were behavioural problems, disaffected children; the whole social milieu is very difficult. But at least when there’s so much room for improvement, you can only move up. The pressure at a school like Kendrick, when you’re regularly in the top five nationally for results, is to continually find ways to stay at the top, which is also quite tough.”

Pupils from Kendrick got involved with Ashmead pupils on a summer literacy scheme, and Kendrick families were supportive of the temporary appointment, says the head. “Staff were proud, and pleased. They felt it was acknowledgement for us, that we had something to offer the community.” There was also a feeling among governors that having the local authority effectively owing the grammar school a favour - at a time when selection appeared to have a question mark over it - was no bad thing.

But her two terms’ involvement at Ashmead shook up Marsha Elms. “It made me cross with the system, with Ofsted and with the Government, that they thought there were easy answers. And I’m still cross with the Government for the burdens it is putting on teachers. It made me feel much more political.”

She rings up a few days later with a coda. During her summer term as acting head, GCSE exam results at Ashmead rose from 6 per cent five A-Cs to 10 per cent. “I got every bit as much pleasure from that increase as I did coming back to Kendrick and finding it was 100 per cent,” she says.

The Government proposed in March that “superheads” could run clusters of schools, an initiative which has yet to get off the ground. The number of heads with experience of running even two schools is low - in the tens rather than hundreds. But the experience of those who have tried it seems to underline the need for schools to have a headteacher in situ, even if mentored or managed by someone further up a management line.

Angeles Walford, head of the 520-pupil Priory C of E middle school in Wimbledon, south London, has twice stepped in to act as head of troubled schools, once for a term and once for two. She would not do it again. “I feel my own school has suffered,” she says. “Parents miss you, teachers miss you and although the acting head does everything, it is a difficult job for them, knowing that the headteacher is coming back.

“What is needed is a pool of recent headteachers seconded to the borough for a year or two, or three, in each borough. But of course they can’t afford it. Chris Woodhead is creating these failing schools and the Government has got to get its collective head round the solution. You need the local authority, school and parents working together to make improvements. Taking other headteachers out of their own schools is not the answer.”