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Introduction to managing sexual offenders and violent offenders

Authorised Professional Practice

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This page is from APP, the official source of professional practice for policing.

First published
Written by College of Policing
Managing sexual offenders and violent offenders
16 mins read

Modules of this APP are currently under review. Implications for the UK leaving the European Union are also being examined.

See APP on International investigation for latest available detail on specific areas, for example:

  • International Law Enforcement Alerts Platform (I-LEAP)
  • European Union Agency for Law Enforcement Cooperation (Europol)
  • International Criminal Police Organization (INTERPOL)
  • joint investigation teams

This guidance provides an introduction into the principles of public protection and effective multi-agency work, recording information on the Violent and Sex Offender Register (ViSOR), roles and responsibilities and making decisions based on risk management. It explains the importance of:

  • training and development
  • management responsibilities
  • staff welfare
  • the police role in effectively managing sexual offenders, violent offenders and potentially dangerous persons (PDPs)
  • manageable workload
  • ensuring management of sexual offenders and violent offenders (MOSOVO) units are staffed appropriately

The management of sexual offenders and violent offenders (MOSOVO) and PDPs require coordinated action by several partners and is subject to inspection and review by a number of bodies. These include:

  • His Majesty’s Inspectorate of Constabulary and Fire & Rescue Services (HMICFRS)
  • His Majesty’s Prison and Probation Service
  • Independent Office for Police Conduct (IOPC)

Protecting the public

Protecting the public is the responsibility of all police officers and staff working in the police service, but the police can’t achieve this alone. Chief and senior officers are responsible for creating the structures that support the multi-agency coordinated approach that is crucial to ensure that the risk posed by sexual offenders, violent offenders and PDPs is managed appropriately and effectively.

Managers in charge of response policing should ensure that intelligence is used to equip patrol and response officers with the relevant information they need to fulfil their roles in the monitoring and management of such offenders.

All officers and staff must understand that their observations and knowledge, properly recorded, help to inform the intelligence picture and ensure that offenders comply with conditions placed upon them.

Officers and staff should investigate all offences thoroughly. They should collect and record fit-for-purpose intelligence in an accurate and timely manner in accordance with APP and local policy and procedure.

Supervisors and managers should ensure that officers and staff have sufficient time and support to carry out investigations to a high standard. This allows the police service and other agencies to collect significant information about patterns of offending, prevent and disrupt offending and provide information to courts for the purposes of reaching verdicts, sentencing and issuing civil orders.

Supervisors of first responders must check the quality of intelligence submissions, considering them as a key part of performance assessments. Those managing intelligence systems should check the general quality of submissions and ensure that, as far as possible, they are of high quality and are used effectively to create useful intelligence products that help to make people safer.

Multi-agency approach

Policing operates within a system of service deliverers. If officers and staff at all levels are to be effective in managing risk, there must be an effective collaborative structure.

To work effectively with multi-agency public protection arrangements (MAPPA) and other multi-agency structures, chief officers should:

  • ensure that appropriate authority to commit resources is delegated to the right level
  • ensure police officers and staff have the skills and competency to perform their role under MAPPA
  • ensure the force is represented appropriately at multi-agency public protection (MAPP) meetings and the strategic management board (SMB)
  • ensure the force is represented appropriately at meetings of other multi-agency structures, including community safety partnerships, local criminal justice boards and local safeguarding children and adult boards
  • coordinate the police contribution to MAPPA with other public protection multi-agency structures
  • contribute to joint agency initiatives, such as providing a MAPPA coordinator
  • challenge partner organisations to deliver against their obligations, ensuring that the police are not expected or required to take on duties beyond their responsibilities and/or competence

Each chief officer should also ensure that the force has an appointed public protection lead at National Police Chiefs' Council (NPCC) level. The role of the lead is to ensure that individuals working to manage offenders are operating within a supporting, comprehensive system.

The public protection lead should:

  • make sure that there is a comprehensive system to manage violent and/or sexual offenders and PDPs, including force policies and procedures and arrangements with partner organisations
  • incorporate a public protection strategy into the Police and Crime Plan
  • lead on public protection issues in the force and report to the chief constable
  • ensure there are sufficient prescribed police stations in accordance with the Sexual Offences Act 2003 (Prescribed Police Stations) Regulations 2015
  • represent the force on the MAPPA strategic management board
  • provide a strategic link between the force and the National Probation Service (NPS)/Community Rehabilitation Company (CRC) and prison services
  • integrate MAPPA and potentially dangerous persons (PDPs) policy into other areas of public protection, including policies on investigating serious sexual offences, child abuse, vulnerable adult abuse, domestic abuse, hate crime, missing persons and managing prolific and priority offenders
  • ensure local procedures are in place for the transfer of risk assessment data and other records including management activities and issues, if and when offenders or PDPs move from one force area to another

Other multi-agency structures

In addition to MAPPA, there are several other multi-agency structures relevant to public protection.

For specific detail, see:

In some areas, local criminal justice boards also have a role to play.

Offender types

The section identifies the types of offenders who may be managed by a MOSOVO unit. See Identification of MOSOVO offenders for full definitions.

Those subject to management under Part 2 of the Sexual Offences Act 2003. Requirements for registering and managing offenders are specified under Part 2 and form the framework for offender management.

For further information see:

Registered violent offenders (RVOs)

  • Those made subject of a violent offender order under section 98 of the Criminal Justice and Immigration Act 2008.

Registered terrorist offenders (RTOs)

  • Terrorist offenders who are subject to notification requirements under the Counter-Terrorism Act 2008.

MAPPA Category 2 violent offenders

  • Offenders with a conviction for a relevant violent offence that falls under MAPPA.
  • Offenders with a conviction for a sexual offence not included as Category 1.

MAPPA Category 3 other dangerous offenders

  • Those with a conviction that shows they may be a risk to the public and are actively managed by MAPPA.

Potentially dangerous persons (PDPs)

  • PDPs subject to active management (see Potentially dangerous persons). This may include prolific and priority offenders who fall under MAPPA management.

Note: This list is not exhaustive.

Offender management

An investigative approach, underpinned by respectful scepticism, is central to every stage of managing MOSOVO offenders and PDPs.

Managers and supervisors should ensure that their officers and staff have access to all appropriate information and question any gaps. Detailed intelligence reports contribute to risk management and should include information about modus operandi, patterns of offending and other behaviour and associations of the offender.

At each stage in the offender management process, staff need to be able to justify their decisions based on available documented information. Decisions are usually considered justifiable if staff (at all levels of responsibility) have:

  • collected, recorded and thoroughly evaluated all available information
  • followed policies and procedures
  • used reliable assessment methods where available
  • taken all reasonable steps and acted on any relevant information
  • communicated with each other, with other agencies, been effective and proactive, and have adopted an investigative approach

The Violent and Sex Offender Register (ViSOR) is a national multi-agency database recognised as a key tool in the effective management of offenders and other persons posing a risk of harm to the public. Its effectiveness is dependent on the quality and timeliness of information and intelligence recorded within it, and consistency in the interpretation of that data. Use of the database must comply with published national standards.

Effective information management is particularly important for ViSOR records managed by the NPS. These records should be maintained and updated with relevant new police information. The manager of the force MOSOVO unit is responsible for ensuring that all police officers and staff know which offenders are on licence and/or are MAPPA-eligible. The manager and staff must also be aware of potential risks and issues and, if relevant, pass information they have gathered from working with the offender(s) to the NPS or CRC as appropriate. This applies especially to category 2, level 1 offenders.

Managing offenders with accurate risk management

When managing sexual and violent offenders and PDPs, staff should make all decisions based on available, accurate information. Each case should be assessed on individual circumstances and informed by static and dynamic risk models.

The police service and His Majesty’s Prison and Probation Service are now using common models and tools to support consistency in the identification, assessment and management of risk in relation to offenders and PDPs.

All forces apply the Offender Assessment System (OASys) Sexual reoffending Predictor (OSP) for (actuarial static) risk assessment and the Active Risk Management System (ARMS) for dynamic risk assessment. Both are taken into consideration when creating an ARMS risk management plan. Chief officers and senior managers must ensure that MOSOVO officers are trained in the use of these tools. See Identifying, assessing and managing risk.

Public protection and neighbourhood policing

Police officers and staff should be aware of the local situation and the potential for sexual and violent offences to make communities feel unsafe. The presence of violent and/or sexual offenders or PDPs within communities can also make communities feel unsafe. This allows them to gauge feelings of tension and vulnerability in the community and predict factors likely to affect it. They should be aware of feelings of vulnerability and insecurity, as well as the economic, political and social factors which affect a community.

Officers and staff can develop their local awareness by:

  • discussing these issues openly
  • describing measures that police and other organisations take to manage offenders and make the public safe
  • acknowledging that risk is reduced but not removed
  • environmental scanning
  • collating and analysing community intelligence and information
  • encouraging communities to report concerns to inform the intelligence picture

As more offenders are registered under MAPPA, collecting and disseminating information and intelligence about them becomes increasingly important. Information sharing and partnership working is critical for MAPPA. Neighbourhood policing teams (NPTs) are key contributors of local community information and awareness.

During times of community tension, local and recognisable officers should maintain a high-visibility police service. These officers should be familiar with the community and its issues. Policing should be in partnership with key community representatives. This allows officers to gather information and intelligence and to manage and contain rumours. Chief officers and senior police managers should consider a communications strategy to put as much information as possible into the public domain to prevent rumours inflaming community tensions.

NPTs should be notified, as appropriate, about the details of sexual and violent offenders and PDPs in their geographic area, and consider this alongside other tasking information. NPTs should be viewed as fundamental to managing these types of offender and can help manage individuals, for example, by supporting the enforcement of civil orders. NPTs can be key sources of community public protection information, including information about identified offenders and PDPs.

Managers of MOSOVO units should ensure that there are well-defined communications procedures with NPTs. Chief officers should implement a system, with appropriate security safeguards, that allows the MOSOVO unit to share pertinent information with NPTs. Information and intelligence entered into such a system must be timely and accurate and allow the MOSOVO unit to notify other agencies of public protection needs. This could include communicating with a prison or the NPS or carrying out procedures for recalling an offender to prison under licence conditions.

For further information see the APP on Engagement – Community impact assessments.

Young offenders

Special considerations may apply to the management of young offenders. Research carried out by Victim Support found that young offenders are particularly vulnerable to being harmed by others and becoming victims of crime. Depending on the young offender’s age and circumstances, children’s social care or local education authorities and/or special educational needs coordinators should be involved, to ensure young offenders have their educational and other needs met.

If a young person is in care, they remain the responsibility of children’s social care, although there should be dual case management with the youth offending team (YOT) if a MAPPA referral is required.

For further information see:

Roles and responsibilities

MOSOVO units

The way forces configure and staff their MOSOVO units varies. Each force should ensure that all new public protection staff are adequately trained, and that existing staff are afforded opportunities for their continuing professional development (CPD) through appropriate training.

Workloads relating to offender management must be manageable. The assessment of what constitutes a reasonable number of cases to manage must include a scrutiny of the risk level ratios (very high, high, medium or low) being managed by case officers.

The current model practiced in force suggests that a maximum of 20 per cent of the caseload should be of a high risk level. This is essential for the safety and welfare of officers, for resilience during periods of staff absence (for example, sickness, annual leave, cover, vacancies and other absences) and for ensuring effective and proactive management of offenders. Workloads should take into account the:

  • size of the geographic area
  • population
  • number of approved premises in the area
  • number and type of offenders and PDPs requiring management

There should be clear and auditable managerial scrutiny of these arrangements, undertaken regularly and in a timely manner. Such systems should recognise the difficulties with mutual cover arrangements which can create pressure and affect the quality of work.

Managers of MOSOVO units should:

  • ensure all staff involved in managing sexual offenders, violent offenders and PDPs are trained to identify, assess and manage risk
  • be responsible for the welfare and wellbeing of unit staff
  • ensure that APP relating to specialist investigations is fully implemented
  • establish systems and processes to meet police responsibilities regarding registered sex offender notification requirements
  • establish systems and staffing arrangements which maximise the benefits of home visits when monitoring offenders and managing the risks they pose
  • ensure that covert investigation resources can be accessed by the MOSOVO unit
  • ensure that available court orders and sentences are appropriately enforced and monitored, and applied for when necessary
  • ensure that officers and staff from other areas of policing are engaged appropriately in managing these offenders, for example, first responders, investigators and NPTs

MOSOVO officers

The selection procedure for staff working in this field should assess an individual’s skills, motivation, suitability and capacity to deal with complex offender management and related issues. Both police officers and police staff can work as MOSOVO and ViSOR officers and should be vetted before taking up their post to a minimum of NPPV2. They should also be regularly vetted while in post (at least every three years). This vetting process should be in accordance with ViSOR standards and APP on vetting.

MOSOVO unit managers should ensure that officers receive adequate administrative and intelligence-led support to help them:

  • carry out their duties
  • fulfil responsibilities to the public
  • ensure the welfare, health and safety of staff

It is good practice for MOSOVO officers to:

  • carry out timely checks with probation and other agencies to ensure all information regarding offenders managed by the police is current and relevant, particularly with regards to MAPPA level 1 cases where there are no regular meetings to facilitate information sharing
  • implement, review and update fit-for-purpose information-sharing agreements or protocols to avoid poor or non-existent communication


The College of Policing has developed specialist training for police officers and staff responsible for managing sexual and violent offenders.

MOSOVO officers should complete the following.

  • Professionalising Investigations Programme (PIP) level 1.
  • The national MOSOVO course delivered by force or regional trainers (this includes training in the theories of Sexual and Violent Offending (TSVO) and the ARMS). Grandfather rights exist for those staff trained in MOSOVO pre-2014, but they must complete ARMS training and be occupationally competent.
  • OSP training – arranged locally.
  • MAPPA – arranged locally.
  • ViSOR system-based training.
  • Child Sex Offender Disclosure Scheme (available via College Learn).

Welfare and safety

In accordance with the duty of care placed on chief officers, all forces must have in place risk assessments, policies and procedures to ensure that the duty to consider the safety and welfare of staff is fulfilled. Supervisors of operational staff and their managers should:

  • ensure that staff are aware of stress, available coping strategies and resources, and where and how to seek help
  • monitor staff proactively and provide them with appropriate support
  • ensure that independent and confidential counselling for MOSOVO officers and their supervisors is available and carried out at regular intervals
  • provide adequate absence management, including sickness and maternity or paternity or family leave cover
  • carry out risk assessments before staff escort offenders
  • carry out risk assessments for home visits to offenders before staff visit the offender’s premises, and record these on ViSOR

For further information see Striking the balance between operational and health and safety duties in the police service (Health and Safety Executive).

Recognising diversity and responding appropriately

The Equality Act 2010 and the Human Rights Act 1998 require an appropriate response to all diversity issues. For example, some offenders whose first language is not English or who have hearing problems may need translation or interpretation services. Staff should record their recognition of and responses to diversity issues in case files.

Although the police have duties under diversity and equality legislation, the fear of being accused of discrimination, such as racism, should not divert staff from acting on risks to the public. For example, even if an offender’s country of origin has different laws about consent to sexual intercourse or the age of consent, it is irrelevant in terms of any offences committed in the UK. Abuse is abuse.

Investigative approach

At each stage in the offender management process, staff need to be able to justify their decisions based on available information.

Offenders’ responsibility

Although the police and other agencies are tasked with protecting the public, offenders are responsible for their own behaviour.

Agencies under MAPPA should work with offenders to reinforce their capacity to control themselves and manage their own risk. This could involve using a combination of agency responses to help offenders identify triggers that increase their likelihood of offending, and teaching them tactics to avoid risky situations.

Not all offenders will be responsive to this approach and they should be assessed on an individual basis. Encouraging offenders to take responsibility for their behaviour is a complex process for all agencies.

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