Exploring escalation and de-escalation within London Stop and Search encounters captured on Body Worn Video

Research Institution / Organisation

The Mayor's Office for Policing and Crime (MOPAC)

In Collaboration With

Strategic Insights Unit (SIU), Metropolitan Police Service

Principal Researcher

Dr. Paul Dawson

Level of Research

Professional / Work-based

Project Start Date

November 2021

Research Context

​The published Mayoral Action Plan sets out the means by which to improve the levels of trust and confidence in Black Londoners. This includes many activities directed towards S&S, but also identifies a valuable method of exploring these encounters – in terms of making best use of Body Worn Video (BWV).

Across 2014/15, the MPS and MOPAC (alongside the College of Policing) collaborated to pilot and evaluate Body Worn Video technology within London. This resulted in the largest Randomised Control Trial into the technology in the world (at the time) which reported favourable results. Subsequently, the innovation was rolled out across London with over 22,000 cameras to front line officers, PCSOs and specialist teams.

BWV data itself provides an innovative opportunity to consider S&S encounters, generating a new perspective into police/citizen encounters. This perspective is not available through other means and is one that can be systematically coded from which to develop new insights that will ultimately lead to new learning on the Stop encounter, specifically issues on escalation/de-escalation.  The resultant benefits include identifying good practice, the potential for improved supervision and training for officers with implications for the wider trust and confidence of policing.

Research Methodology

​The Metropolitan Police Service Strategic Insight Unit (MPS SIU) are already embarking on a project that looks at police-public interactions and improving supervision through coding BWV encounters with MPS Staff completing the coding. Whilst highly valuable, the SIU project is not able to richly explore issues pertaining to escalation, de-escalation and the associated trigger points.


To progress the research, it is proposed that the SIU approach is the core foundation from which additional aspects could be jointly built upon, ensuring the work is able to progress legally whilst also seeking to deliver the outcomes and learning as outlined earlier.

The joint project seeks to conduct the systematic coding of between 4-500 Stop and Search instances captured on BWV technology.

The coding would cover the following main themes:

  1. Scene Details: this section is designed to gain an initial understanding of the physical scene and contextualise the S&S encounter; 

  2. Opening: Defined as the first interaction between the citizen and the officer until the physical search takes place. Includes GOWISELY and officer and citizen’s disposition measures; 

  3. During: the physical search takes place; 

  4. Outcome: the formal outcomes (e.g., cannabis warning, arrest), is the item found, officer/citizen disposition measures;

  5. Reflections: Encounter and technical issues; and 

  6. Time-coding: focussing on verbal and physical behaviours by citizens and police officers associated with escalation in the use of force throughout the stop and search encounter.


Coding in the proposed framework is relatively detailed, typically going beyond the basic ‘yes/no’ format. For example, in the coding of GOWISELY ‘Does the officer give a clear explanation for the grounds for suspicion?’ the response options are:

  • Yes, in response to being asked by the citizen 

  • Yes, on his/her own initiative 

  • No, the citizen asked but the officer did not tell them 

  • No, the citizen did not ask and the citizen did not tell them 

  • No, but explained by another officer

The time-coding methodology draws on previous research undertaken by the College of Policing and Sytsma et al (2021) to identify specific citizen and officer actions/behaviour (verbal and physical) associated with escalation in the use of force in stop and search. Coders will be recording when/if these aspects are observed throughout the stop and search encounter, together with details of the use of force to highlight both the specific points of escalation/de-escalation as well as the relationships between behaviours and these outcomes. Other factors associated with escalation (the presence of bystanders, for example) will also be time-coded. The coding framework has been finalised following discussions between MOPAC Evidence & Insight and the SIU.

The project will begin with a small-scale pilot of the new coding frame (x20 cases).

A process of quality control would be devised for the coding itself – predominantly focusing upon double-coding.

Date due for completion

September 2022
Return to Research Map