Executive Coaching London: One-to-One Coaching for Senior Leaders, With Rehearsal

Some things cannot be talked through, they have to be practised. Executive coaching is good at the talking. A senior leader sits with a coach, names the pattern and decides what to do differently. Then the board meeting turns hostile, the adrenaline is up, and the old pattern returns.

Sidestream's executive coaching is built for that gap. It is one-to-one coaching for a single senior leader, delivered by our co-founders. Where a hard moment is coming, the leader rehearses it first with a professional actor. Because real behaviour change happens through lived experience, the rehearsal is what makes the coaching hold.

This page is for senior leaders in companies, and for the HR directors, Chief People Officers and chairs who commission coaching for them. The page runs to roughly 3,000 words.

What Executive Coaching Means at Sidestream

Executive coaching is structured, confidential one-to-one development for a senior leader. It works on how the leader leads. That means the judgement they bring to hard decisions and the presence they hold in front of the board and the workforce. It also means the way they carry people through change.

The coaching itself is non-directive. The coach does not supply the answers. Structured questions and reflection, often through a framework such as the GROW model, help the leader reach their own clarity and commit to action. Where the leader also needs direct advice, we blend in mentoring. The difference between the two is set out in our guide to coaching vs mentoring.

Two features set the work apart. The first is the systemic lens. The leader is read inside the team, the hierarchy and the structures they work in, not as an isolated individual. The second is rehearsal. What the leader works out in the coaching room is practised under pressure before the real moment. That turns an intention into a behaviour.

Coaching, Group Training or Public Sector Coaching: Which Page Is Yours?

Sidestream runs three senior development offers that are easy to confuse. They share a method, diagnose, rehearse with professional actors, embed, but they serve different briefs. The table shows which page fits which brief.

The distinction matters for the brief. If the behaviour you want to change belongs to a team, coaching one member of it rarely shifts it. If it belongs to one leader, a group workshop dilutes it. Many organisations need both, and the two can run side by side.

Who Coaches: Ben Laumann and Sebastian Flack

Co-founders Ben Laumann and Sebastian Flack coach individual leaders one to one. Who coaches depends on the leader, the brief and the language of the work. Both bring a different half of the same method.

Ben Laumann is Co-Founder and Managing Director UK of Sidestream. He is an organisational psychologist and a theatre director. His grounding runs through UCL, Cambridge and Bocconi, alongside an MA in Acting from the Royal Birmingham Conservatoire. He is a member of the British Psychological Society. That pairing of behavioural science and the rehearsal room is the one the whole consultancy is built on.

Sebastian Flack is Co-Founder of Sidestream and leads our work across Germany and the wider DACH region. He is a systemic coach, supervisor and consultant. He trained as a systemic coach in 2022, then in systemic consulting and coaching and as a supervisor in 2024. He has taught at EvH Bochum since 2018.

Sebastian brings the half of behaviour change that a slide deck can never reach: the human system around the person. In coaching, that means reading a leader inside the teams, hierarchies and structures they sit in. For organisations in Germany and the wider DACH region, he is the first point of contact.

Why Coaching Alone Often Stops at Insight

A coaching conversation can produce real clarity. A leader understands exactly how they want to handle a hostile board question or a confrontation with a senior peer. Understanding it is not the same as doing it when the moment is real and the adrenaline is up.

Our own research points the same way. In a randomised 2020 UCL study by co-founder Ben Laumann (n = 57), people learned a feedback model in one of three ways. The three were a slideshow, a video and a short online session with a role-play coach. Rehearsal with the role-play coach produced significantly better delivery, rated blind by two independent assessors (Cohen's d = 0.75 to 1.08).

The confidence data matter even more for coaching. Self-rated confidence rose after every format, with no significant difference between them, even though blind-rated behaviour did differ significantly. The study found no relationship between participants' confidence and their blind-rated performance.

That is why we do not judge coaching by how the leader feels at the end of a session. A leader can leave feeling ready and still fall back under pressure. The study has limits. It tested an online session of at most 20 minutes, not our coaching, and it is unpublished. The method and its limits are on our research page, and the confidence results are discussed in confidence is not competence.

How Rehearsal With Professional Actors Fits Into Coaching

We pair the coaching conversation with rehearsal. Professional actors play the people a senior leader actually faces. That might be the sceptical board member, the investor who presses on the numbers or the senior peer who resists. Teams preparing a pitch together can rehearse the investor presentation in our presentation skills training.

The leader practises the conversation, gets honest feedback and practises it again, until the intended behaviour holds under pressure. The coaching then works with what the rehearsal showed. That might be the moment the composure slipped, or the question the leader avoided.

This is the logic of deliberate practice described by Ericsson (2016). Skill grows through repeated attempts at the hard part, each followed by feedback, not through understanding it. A rehearsal can follow a written scenario or the leader's own real situation. The difference is explained in real play vs role play, and the method in our role-play training guide.

Moments Senior Leaders Typically Rehearse

The six moments below mirror the behavioural targets we rehearse with senior teams on our executive training, applied to one leader at a time:

• Challenging and being challenged in the executive committee, without the conversation turning defensive.
• A board or investor presentation where the hardest question is the one you hope nobody asks.
• Leading the senior team through a transformation they did not choose.
• Giving difficult news to the wider workforce, and taking the questions that follow.
• A difficult conversation with a senior peer or a direct report about performance or behaviour.
• Holding composure in a reputational crisis, in front of the board, the media or a regulator.

The list is a starting point, not a menu. Each rehearsal is written for the leader's own situation. Names and details are changed where confidentiality requires it.

How an Executive Coaching Engagement Runs

Every engagement follows the same four steps. The content of each step changes with the leader.

1. Scoping. The leader and, where appropriate, their sponsor agree the behavioural goals. If coaching is not the right format, we say so at this point.
2. Coaching. Confidential one-to-one sessions, non-directive at the core, blended with mentoring where the leader needs direct advice rather than questions.
3. Rehearsal. Before a specific high-stakes moment, the leader practises it with professional actors, then works through what happened.
4. Review. Progress is reviewed against the agreed goals as observed behaviour in real work, not against how enjoyable the sessions were.

Engagements are shaped around the leader rather than sold as fixed packages. Possible formats include a focused individual coaching programme over several months and a blended coaching-and-mentoring engagement. Others combine coaching with rehearsal for one specific high-stakes moment, or prepare a leader for a bigger role. Sessions run on-site, virtually or hybrid, and every format is priced per engagement.

Coaching for Succession and New Roles

Coaching is not only for leaders already in post. It can also prepare a leader before the next role, not only support them once they hold it.

Coaching changes that. By working on self-awareness, decision-making and presence before the move, it helps a successor arrive ready rather than learning in full view. The harder demands of the future role can be rehearsed before the leader holds it. That makes readiness observable rather than assumed. For the group side of the same problem, see our page on new manager training.

Confidentiality and the Role of the Sponsor

Executive coaching only works if the leader can speak freely. The coaching is confidential. All Sidestream consultants and contracted professional actors operate under appropriate confidentiality protocols. Scenario content and the identity of the leader are not shared outside the engagement without permission.

Where an organisation commissions the coaching, a sponsor usually helps set the goals. A typical design would agree at the outset what is reported back, and in what form. The leader then knows where the line sits before the first session.

How We Measure Executive Coaching

Coaching that cannot be evidenced is hard to defend to a finance director, and rightly so. We measure at Kirkpatrick Level 3: observed behaviour in real work, not satisfaction alone. Goals are agreed at the outset with the leader and, where appropriate, their sponsor.

Progress is then reviewed against those goals. Typical evidence is how the leader chairs a meeting, handles challenge, communicates through change and decides under pressure. Where the brief allows, Level 4 organisational indicators are added. Our guide to the Kirkpatrick model sets out the levels, and how to measure behaviour change covers the practice.

We do not use the leader's self-rating as the main measure. Our own study is the reason: it found no relationship between participants' confidence and their blind-rated performance. A leader who feels better is a good sign, not a result.

When Executive Coaching Is Not the Right Choice

Coaching is not the answer to every senior development brief. If the problem sits in how a whole team works together, executive training for the senior team will do more. If managers across the organisation need to coach their own people, coaching skills training is the better fit.

If a leader wants to qualify as a coach, they need an accredited coach-training programme, which we do not run. If the leader works in the civil service, government or policing, our public sector executive coaching is built for that context. And if what a leader needs is a sounding board without a behavioural goal, a mentor may serve them better. We will say so in the first call.