You could say Paul Smith wrote the book on amalgamating schools - or at least, the thesis. In the turmoil of London education in the 1980s, as pupil numbers crashed, he helped amalgamate four schools into one not once but twice, first in Hackney and then in Peckham.

Luckily, it made useful material for his degree.

Both were in response to huge falling rolls, and both were a “painful process”, says Mr Smith, now head of Lyng Hall school in Coventry.

“It was a very tense time,” he recalls. “Those teachers that were happiest were the ones that had continuity of head or continuity of building. The least happy were those that were moving building and had a new head.”

Mr Smith’s key advice is to end uncertainty quickly: “If you’re going to do it, do it as fast as possible.If you’ve got four heads of maths going for one job, then if you delay, the danger is that the good one won’t wait.”

Both amalgamations took two or three years to carry out, and another three or four years before all the pupils were finally on one site. That, Mr Smith says, was too long. “I spent a lot of time in my car.”

The process created anxiety and uncertainty among pupils. Continuity became important. So, for example, older pupils who had never worn uniform were allowed to stay in mufti on their old site. But the new Year 7, taught elsewhere, had the new colours.

The same held for the mix of house groups and year groups that different schools had employed - the old systems prevailed on the old sites.

Meanwhile, pupils were introduced to each other in five-a-side football tournaments and on school trips to avoid factions developing.

Cliques can occur in the staffroom too. Mr Smith credits both his headteachers for creating a sense among teachers that they were part of a single team. But it can be tough for settled staff who find a stranger in their favourite chair, or who have taught boys for 20 years and now find themselves in front of mixed classes.

“Remember that there will be grief - somebody who’s been head of department for years and doesn’t get the job. They require careful handling,” he says, but adds: “Handled well, you end up with a surge of energy and relief that at last you’re working in a decent-sized school.”

Openness is important. And though disaster might seem more likely, you’ll probably get your best results in the year the old school closes. “It’s the dedication of teachers who are determined pupils won’t be affected.”

Mr Smith expects to be retired by the time numbers become an issue again in Coventry. “I’ve seen my last amalgamation,” he says.

But he has this final word: “Both pupils and staff are far better off with amalgamation than working in a school that’s getting smaller and smaller, however painful the process. People shouldn’t dread it.”

Advice on closing a school will appear in this slot at the end of November