Active Bystander Training in London

What Active Bystander Training Is

A bystander is anyone present when conduct crosses a line who is neither the target nor the person doing it. An active bystander interrupts, checks on the person targeted, or reports it. Robertson and Steele published a survey of English NHS Trusts in 2023. They describe active bystander training as training that has been promoted to address sexual harassment, alongside other forms of poor behaviour, discrimination, and harassment.

Acas covers this in its guidance on witnessing sexual harassment. You could try to stop it if you feel it is safe to do so. You should talk to the person who experienced it to see if they want your support. And Acas calls it a good idea to make a note with dates, times and names. Each is something a person does, under pressure, with colleagues watching.

Provision is thin. Of the 199 Trusts that responded, 35 provided active bystander training. Most of it was not specific to sexual misconduct, and was opt-in only. Knowing that you could interrupt is not the same as being able to interrupt.

The Legal Basis: Section 40A, and 30 October 2026

The duty is one sentence, set out in Section 40A of the Equality Act 2010. It reads: "An employer (A) must take reasonable steps to prevent sexual harassment of employees of A in the course of their employment."

It was inserted by the Worker Protection (Amendment of Equality Act 2010) Act 2023. It extends to England, Wales and Scotland, and has been in force since 26 October 2024. Under section 124A, a tribunal that finds sexual harassment may add up to 25% to compensation where section 40A was also breached.

On 30 October 2026 the bar rose. Section 20 of the Employment Rights Act 2025 inserts the word "all" before "reasonable steps". The date is set by commencement regulations, S.I. 2026/1065. The Government's implementation timeline, updated 5 November 2026 lists the "all reasonable steps" duty under that date. It also lists "introducing an obligation on employers not to permit the harassment of their employees by third parties".

Acas has published a note on the change. Among the steps to consider, it lists "sexual harassment training that is suited to your organisation, making use of specialist delivery where needed". There is more in our piece on the October 2026 bar and in harassment prevention training in London.

No statute names active bystander training. Whether a programme is a reasonable step is for the organisation and its advisers to judge. A bystander who has practised the interruption is a different piece of evidence from a completion certificate. FCA-regulated firms carry a second set of expectations on the same conduct. They are covered in our guide to the FCA non-financial misconduct rules.

Why a Policy Does Not Produce a Bystander

Darley and Latané's 1968 paper carries the mechanism in its title: Bystander intervention in emergencies: diffusion of responsibility. Fischer and colleagues' 2011 meta-analysis in Psychological Bulletin found an overall effect of g = -0.35. The presence of other people makes it less likely that any one of them helps.

In a 2024 quasi-experiment, a 90-minute interactive training for field staff of a US state government agency raised participants' likelihood to report incidents, but "institutional reports remained low". Intent moved faster than the system around it.

The effect was weaker where the situation was perceived as dangerous, a perpetrator was present, or the cost of intervening was physical. A remark in a meeting is not dangerous, and the cost of interrupting it is social. But the person who made it is in the room, and the others are usually colleagues rather than strangers. The meta-analysis also found the effect weaker under those two conditions.

A policy puts no sentence in anyone's mouth for a moment that lasts about three seconds. That is why the duty needs behaviour rather than a document.

A module also feels as if it worked. In the randomised 2020 UCL study behind our method, 57 participants learned the same feedback skill. They learned it through rehearsal with a role-play coach, slides or video. They rated their own confidence three times: before the intervention, after it, and after a simulated conversation.

Confidence rose in every group (Laumann (2020), UCL, unpublished research paper, Figure 4). Slides went 4.46, 5.00 and 5.39. Video went 4.69, 5.13 and 5.38. Practice went 4.27, 5.33 and 5.53 (confidence ratings n = 44). Modality had no significant effect on confidence (p = .958), nor did the interaction of time and modality (p = .541).

Observed delivery, rated blind by two independent assessors, differed. Rehearsal came out ahead of slides (Cohen's d = 0.75) and of video (d = 1.08). The study tested one skill. Its practice condition was an online role-play coaching session of at most 20 minutes. It was not this programme, and we do not present it as a measurement of it. It does suggest why a feedback form is a weak guide. Self-rated confidence rose in every group, whatever the observed delivery.

Four Moments, Rehearsed as Scenes

We write scenarios from the organisation's own material. A short scoping step establishes where conduct crosses the line in this workplace, and the actors are briefed on those specifics. A typical bystander design would build around four moments. Each is a scene with one sentence the participant has to say, out loud, to an actor. The actor responds as a real person would. Feedback and a second attempt follow. The lines below are illustrations, not a script.

The remark in the meeting. A comment about a colleague's body or private life lands and the agenda moves on. The move is one flat sentence in the next half-second: "Let's not do that. Back to the numbers." Rehearsal would work on speed and tone. Ten seconds late, or delivered as a lecture, and the room moves the wrong way.

The senior person nobody challenges. The remark comes from whoever signs off the budget or the appraisal. The sentence has to hold without becoming a confrontation or an apology. For example: "I'd rather we didn't talk about her like that." The scene would also rehearse the fallback Acas describes. That fallback is reporting it, for the day when saying it in the room is not safe.

The client who crosses the line. From 30 October 2026 employers must also not permit harassment by third parties. The client in the meeting room is where that is tested. The sentence would go to the client, in front of the colleague it was aimed at: "I'm going to stop you there. We don't do that here."

Afterwards, with the person it happened to. Acas's guidance is to ask whether they want your support. The conversation goes wrong when the bystander decides for them. The scene would rehearse the offer without the takeover: "I saw what happened. Do you want me to say something, or would you rather I didn't?" Then the note: what, when, and who else was there.

Format, Cohort and Follow-up

Sidestream is a behaviour change consultancy based at 58 Malden Road, London NW5 3HG. Most of this work is delivered in-house at client offices across London. A typical format is a half-day of four hours with 5 to 30 participants and one or two scripted scenarios. A participant can also bring a conversation of their own: the one still owed to a colleague after a moment they witnessed. They then brief the actor themselves. That is real play rather than role play.

Bystander rehearsal alongside disclosure response and manager handling of concerns is the one-day, multi-target format. It is set out on our harassment prevention page. Work is priced per engagement, because the effort sits in the scenario design. Why the other person in the scene is a professional actor is explained in role-play training with professional actors. The cohort that matters is the one present when a remark lands. That is more often a whole team than its managers.

We look at what people do, in the room and in the follow-up simulation, not what they tick on a form. An optional follow-up simulation around 90 days after delivery: each participant books an hour over Zoom, steps into a fresh scenario with a coach they have not met, built around the situations practised in the room, and gets personal feedback.

It is a chance to practise again and to see how much has stuck, not an assessment. Download our four-level measurement framework (PDF), with a worksheet for your own programme.

If your organisation wants to track the change itself, figures most HR systems already hold will do. One is the share of concerns that arrive from witnesses rather than only from the person targeted. Another is the time between an incident and its first report. Both can be read before delivery and again around ninety days afterwards. Setting up Level 3 is covered in how to measure behaviour change and the Kirkpatrick model.

Active Bystander Training in London: In Short

In England, Wales and Scotland, section 40A requires reasonable steps to prevent sexual harassment. From 30 October 2026 the requirement is all reasonable steps, and employers must also not permit harassment by third parties (Employment Rights Act 2025, brought into force by S.I. 2026/1065). A policy describes a bystander; it does not produce one.

Active bystander training in London therefore has to be rehearsal. That means scenes with professional actors, one sentence each, attempted, coached and attempted again. It runs as a half-day for 5 to 30 people, priced per engagement. We look at what people do, in the room and in the follow-up simulation, not at how confident people felt on the way out.

The wider programme, with six behavioural targets, is harassment prevention training in London. The same interruption aimed at bias is Target 2 of DEI training in London. What counts as harassment is in what is workplace harassment in the UK. Raising things before they become incidents is speak-up culture training and how to build a speak-up culture. This page is general information, not legal advice.

Frequently Asked Questions

What is active bystander training?

Training for the people who witness conduct that crosses a line, so that they interrupt it, check on the person it was aimed at and report it, as Acas describes in its guidance on witnessing sexual harassment. Sidestream runs it as rehearsal with professional actors, so the interrupting sentence has been said out loud before it is needed.

Is active bystander training a legal requirement in the UK?

No statute names it. In England, Wales and Scotland, section 40A of the Equality Act 2010 requires employers to take reasonable steps to prevent sexual harassment of their employees, in force since 26 October 2024; from 30 October 2026 the duty is to take all reasonable steps (Employment Rights Act 2025, s.20, brought into force by S.I. 2026/1065), alongside an obligation on employers not to permit harassment by third parties. Whether a programme is a reasonable step is for the organisation and its advisers to judge.

Does it cover harassment by clients and other third parties?

Yes. From 30 October 2026 employers must not permit the harassment of their employees by third parties, and a typical design would make it one of the four moments: a professional actor in the client's chair, the participant stopping it in the room, then the second conversation with the colleague afterwards.

How do you know the training changed anything?

Not from a feedback form: in the randomised 2020 UCL study behind our method, self-rated confidence rose in every teaching condition, including the two whose observed delivery blind assessors rated lower. We look at what people do, in the room and in the follow-up simulation, not what they tick on a form. If your organisation wants to track the change itself, figures it already holds, such as the share of concerns raised by witnesses and the time to first report, can be read before delivery and again around ninety days afterwards.

Where in London does Sidestream deliver active bystander training?

Sidestream is based at 58 Malden Road, London NW5 3HG, and most active bystander training is delivered in-house at client offices across London, as a half-day for 5 to 30 people with professional actors and priced per engagement. The programme is built for one organisation at a time, with its own scenes, and is delivered UK-wide where the work needs it.