Should You Promote Internally or Appoint an Interim Leader?

A practical guide for proprietors, boards and trustees

When a headteacher leaves, most boards look inward first. There’s usually a deputy who knows the school, the children and the staff, and promoting them feels loyal, quick and cheap.

Sometimes it’s exactly right. Many proprietors tell us their best headteacher was the deputy they promoted in a hurry. Others tell us the same decision cost them a good deputy who resigned two terms later, exhausted and unsupported.

The difference between those outcomes is rarely the person. It’s whether the board was honest about what the school needed and whether they resourced the decision properly.

What does internal promotion give you?

Continuity. In a special school or alternative provision this matters more than anywhere. Pupils who’ve experienced placement breakdown notice adults leaving. A familiar face at the top is genuinely reassuring in a way it wouldn’t be in a large secondary.

Knowledge. They know the children, the families, the commissioners, the history and which staff are carrying what. An external leader takes a term to learn that.

Speed. They can start on Monday.

Development. You’re growing your own leader, which is good for them and good for your succession planning.

Cost. An acting allowance is cheaper than an interim day rate. Though as we’ll come to, this is the least reliable of the five.

A message to staff. That there’s a path here, and the school promotes from within.

What does an external interim give you?

Capacity that’s genuinely additional. An interim leader does one job. A promoted deputy usually does two.

Experience of the thing you’re facing. Someone who has taken three schools through a regulatory process, or led a turnaround, or handled a difficult departure before.

Independence. They can name a weak appointment, a failing system or a governance problem, because they didn’t hire anyone here and they won’t be around to live with the reaction.

A clean end. They leave. Nobody has to be un-promoted, and no one becomes an unsuccessful internal candidate for the permanent job.

Protection for your deputy. They stay in the role they’re good at, keep developing, and don’t get burnt out by a job they weren’t ready for.

The question that actually decides it

Not “is our deputy good?” but “is our deputy ready for this school, in the situation it’s in, right now?”

Those are different questions. A deputy might be ready for headship in a settled school and not ready to lead one through a regulatory process, a serious incident or a rebuild of the senior team. That’s not a criticism. It’s a statement about the situation rather than the person.

Two follow ups sharpen it. What happens to their current job if they step up, and can you backfill it? And what does the school need in the next two terms that they haven’t done before?

If the honest answers are “nothing much” and “not a lot”, promote. If they’re “we can’t backfill it” and “quite a bit”, think again.

The trap to avoid

The most common mistake we see isn’t promoting the wrong person. It’s promoting the right person and then not resourcing it.

A deputy is asked to act up. Their own role isn’t backfilled. No allowance is agreed, or it’s agreed vaguely and paid late. No end date is set. Nobody supports them. And the board, having solved the problem, moves on.

Six weeks in, that person is doing two jobs, neither well, and is too proud and too invested to say so. Two terms in, they resign, and you’ve lost a headteacher and a deputy from the same decision.

Many leaders tell us being asked to act up felt like a compliment in September and a trap by February. What changed wasn’t the job. It was the accumulation of everything nobody took off them.

A third option worth considering

You don’t have to choose. In specialist settings the hybrid is often stronger than either.

Promote the deputy to acting head so the children and families see a familiar face leading the school, and bring in an experienced interim two or three days a week above or alongside them. The internal leader brings relationships and knowledge. The external one brings capacity, experience and the ability to be direct.

This develops your deputy properly rather than throwing them in, gives the board an independent read, and costs considerably less than full interim headship.

What it needs is clarity about who decides what. Write it down: who chairs the senior team, who holds safeguarding, who a parent escalates to, who signs off spending. Left vague this creates the confusion you were trying to avoid.

Where a lighter touch is enough, coaching for a first time acting head is cheaper again and frequently all that was actually needed.

What about the permanent job?

Be honest about this at the start, because it’s the thing that damages people.

Tell the acting head whether the permanent post will be advertised externally, and don’t imply that acting up guarantees anything. A deputy who believes they’re being groomed and then watches an external appointment arrive will usually leave.

Equally, don’t rule them out to seem impartial. An acting head who has done the job well for two terms has a stronger evidence base than any interview panel produces.

The fair position is usually an open process where they’re a genuine candidate, said clearly at the outset. What isn’t fair is leaving it unsaid and letting them assume.

From our experience

Boards underestimate the second gap almost every time. The conversation is entirely about whether the deputy can do headship, and nobody asks who does the deputy’s job.

In a small special school that’s frequently behaviour, safeguarding and a teaching commitment. Those don’t vanish. They get absorbed, badly, by someone already doing a bigger job.

We often see the cost arrive as staff turnover rather than as an obvious failure. The acting head copes, the school looks stable, and three good staff leave over a year because the things that held them were quietly dropped.

Schools that promote well are the ones that made a proper appointment out of it: written arrangement, allowance, backfill, end date, support and an honest conversation about the permanent post.

A common misconception

“Bringing in an outsider would demoralise our team.”

It’s a genuine concern and it’s usually the opposite of what happens.

Teams rarely resent an external interim. What they resent is watching a colleague they respect being set up to fail, or a leadership vacuum nobody addresses. Staff are generally more realistic than boards about whether a deputy is ready, and they’re often relieved when capacity arrives.

Appointing externally can be the most loyal thing a board does for its senior team, because it protects them. And it protects the children, who need the adults around them to have enough capacity to do their jobs properly.

Questions for proprietors and boards

• Is this person ready for this school in this situation, or ready in principle?
• Who does their current job, and can we genuinely backfill it?
• What have we taken off them, specifically, and can we name it?
• Have we told them honestly what happens with the permanent post?
• Would the hybrid give us more than either option alone?

Our perspective

Neither answer is better. What matters is being honest about what the school needs for the next two terms and resourcing whichever choice you make.

If you promote, treat it as a real appointment: pay it, backfill it, date it, support it, and be straight about what comes next. If you appoint externally, say clearly that it’s about capacity rather than about anyone’s shortcomings. And consider the hybrid, because in specialist settings it frequently gives you the strengths of both.

Every school’s circumstances are different, but the schools that come through this well are the ones that made a deliberate decision rather than the easiest one, and kept the children’s experience at the centre of it.