What Is the SIA Approved Contractor Scheme, and Why Does It Matter for Your Security Business?

If you operate a private security company in the United Kingdom, the SIA Approved Contractor Scheme (ACS) is likely already on your radar. For many clients (particularly in local government, retail, healthcare, and facilities management) ACS accreditation is not a differentiator. It is a minimum requirement for tendering.

But ACS is more than a compliance checkbox. Done properly, it drives the operational improvements that reduce costs, retain contracts, and build the kind of reputation that generates referrals. Done poorly, as a paper exercise to tick a procurement box, it creates audit exposure without the operational benefits.

This guide explains what the ACS is, what achieving and maintaining it involves, and how the companies that genuinely benefit from it approach the process.

What Is the SIA Approved Contractor Scheme?

The ACS is a voluntary accreditation scheme operated by the Security Industry Authority. It assesses private security companies against the ACS standard, which is made up of seven criteria: strategy, service delivery, commercial relationship management, financial management, resource management, people, and leadership.

Companies that meet the standard become SIA approved contractors. The SIA describes the scheme's purpose as protecting the public and maintaining and improving standards in the private security industry.

Approval lasts three years. To get it, and to keep it, you need a successful assessment every year by an independent assessing body approved by the SIA, which checks your business against the ACS standard. On the standard route, the starting point is the SIA’s ACS self-assessment workbook, which sets out the indicators of good practice that sit under each criterion.

Who Should Pursue ACS Accreditation?

ACS is relevant to any company providing front-line security services under the Private Security Industry Act 2001: manned guarding, door supervision, CCTV, close protection, key holding, and cash and valuables in transit.

The business case for ACS is strongest when:

• You are tendering for contracts with local authorities, NHS trusts, or large corporate clients who specify ACS as a requirement
• You want to signal credibility and operational maturity to prospective clients who are comparing multiple bidders
• You are growing the business and want a structured framework to professionalise your operations as headcount increases
• You are preparing for acquisition or investment, where demonstrating auditable quality management is a due diligence requirement

Smaller companies sometimes view ACS as something for larger operators. In practice, the discipline of going through the assessment process, even for a company with 30 to 50 guards, is one of the most effective ways to identify and fix the operational gaps that limit growth.

The ACS Standard: Seven Criteria

The ACS standard consists of seven criteria, and underneath each one sits a set of indicators of good practice. Approval depends on evidence across all seven, not just the areas your company already handles well. The one-line descriptions below are the SIA’s own.

1. Strategy

“An SIA approved contractor has clear strategic direction enabling it to deliver value to all stakeholders.” This covers having a coherent business plan, clear ways of improving service delivery, handling internal and external communications, and measuring performance against key indicators.

2. Service Delivery

“An SIA approved contractor has robust processes in place that ensure service delivery to its customers and stakeholders.” The SIA’s guidance treats site-specific assignment instructions as the minimum level of documented service delivery process. This criterion also covers continuity planning, incident procedures, and how you ensure staff attend customer sites.

If you use subcontractors, the standard expects their use to be agreed with your customers and covered by defined quality assurance procedures. Approved contractors can only subcontract security services to other ACS businesses, except where the SIA explicitly allows it.

3. Commercial Relationship Management

“An SIA contractor promotes robust and transparent commercial relationships with its customers, consumers and suppliers founded on mutual trust and respect.” This is where your complaints procedure, customer site visits, and how you gather and act on customer feedback sit. Telling an assessor “we have good relationships with all our clients” is not evidence; satisfaction surveys, complaint logs with resolution records, and site visit notes are.

4. Financial Management

“An SIA approved contractor is financially viable with sufficient resources to meet its current and future obligations.” Payroll management, financial controls, a clear management structure with defined authority levels, and insurance that covers your contractual requirements all fall here.

5. Resource Management

“An SIA approved contractor has sufficient technical resources to sustain its business meeting the relevant industry standards.” This covers your management information systems, premises, equipment records, document control, and data protection.

6. People

“An SIA approved contractor develops and implements plans to ensure its people are suitably trained, developed and cared for.” Recruitment, staff records, training and induction, assignment-specific briefings, welfare, working hours, and pay all sit under this criterion. For screening and vetting, the SIA’s guidance names BS 7858 or an equivalent standard.

SIA licence records belong here too. Checking every operative against the SIA’s register of licence holders before deployment, and keeping a record of each check, gives you evidence an assessor can sample. A compliance manager who can show a digital audit trail of register checks across 200 guards is in a far stronger position than one relying on a spreadsheet updated when they remember to. See our complete guide to SIA licence compliance for the detail on licensable roles, renewal timelines, and register verification.

7. Leadership

“An SIA approved contractor has effective leadership.” Leaders need the knowledge and ability to lead a security company, should review and improve their own leadership, and maintain an ethical business culture. When a compliance manager “owns” the ACS process and senior leadership treats it as an administrative task, it shows: assessors interview people at every level of the business, directors included.

The Assessment Process Step by Step

Stage 1: Self-Assessment

The SIA offers two routes to approval: standard and passport. On the passport route, you first get certified through an SIA accredited passport scheme (currently the NSI ACS Passport Scheme). On the standard route, the process starts with assessing your own company using the ACS self-assessment workbook. Be honest with it: this gap analysis, not the formal assessment, is where the work of ACS begins.

Stage 2: Preparation and Evidence Gathering

Once gaps are identified, you need to build or improve the processes and documentation that address them. The evidence you gather at this stage is what the assessor will examine.

Stage 3: Independent Assessment

You arrange and pay for an assessment with an SIA-approved assessing body (British Assessment Bureau, NSI or SSAIB). The assessor samples your activity, interviews people from across the business, including staff on different shifts and remote sites, and contacts customers or suppliers to verify your evidence. To be approved, you need to reach the required achievement level in all relevant criteria and sub-criteria.

Stage 4: Ongoing Improvement

ACS is not a one-off achievement. Once approved, you need a successful assessment every year, an annual return to the SIA, and a renewal after three years. Every one of the seven criteria includes measuring and improving performance, so the standard expects continued improvement, not just maintenance of the status quo.

Where Evidence Usually Falls Short

SIA Licence Records

Assessors test your processes by sampling real activity. If your licence checks are not documented consistently across the deployments they sample, no amount of good process description will make up for the missing evidence.

Client Satisfaction and Complaints

A complaints procedure in the handbook is not the same as one that is implemented. Documented satisfaction surveys, complaint logs with resolution records, and evidence that you act on what customers tell you are what the commercial relationship criterion asks for.

Subcontractor Management

Companies that use subcontractors, whether regularly or for peak demand, often have informal arrangements that work in practice but cannot be demonstrated to an assessor. Under the standard, subcontracting has to be agreed with the customer and covered by defined quality assurance procedures.

How Technology Supports ACS Compliance

A significant portion of the ACS evidence requirement is about demonstrating systematic, auditable processes, particularly in licence management, scheduling, and staff record-keeping. Manual systems are inherently harder to evidence; digital systems create audit trails automatically.

Guard management platforms that integrate with the SIA Public Register generate timestamped records of every licence check. Scheduling systems that require shift confirmation create logs of every rota decision and guard acknowledgement. GPS clock-in records demonstrate the reliability of deployment across every shift over the assessment period.

TacDesk has a Compliance module for UK security companies working within or towards ACS accreditation, included on every paid plan. It scores your readiness across the ACS criteria on a dashboard, holds BS 7858 vetting and training records alongside your other registers, and produces an audit report you can export, so the evidence builds up as part of day-to-day operations rather than as a separate exercise.

Is ACS Worth the Investment?

The SIA charges an application fee based on how many licensable staff you have: £400 for up to 10, £800 for 11 to 25, £1,600 for 26 to 250, and £2,400 for over 250. On top of that there is an annual registration fee of £25 for each licensable individual you deploy, and you pay your assessing body separately for each annual assessment. Factor in staff time for preparation and documentation.

For companies bidding on public sector contracts or working with large corporate clients, ACS is close to essential: many specify it as a minimum tendering requirement. If a single contract you are bidding for requires ACS status, that one win can cover the cost. For smaller companies focused on local residential or retail work, it may be worth waiting until your target market or growth plans make the requirement concrete.

ACS and Competitive Positioning

In a competitive tender, ACS status is table stakes for many public sector and large corporate contracts. But among ACS-accredited companies, there is a wide spectrum of quality. The companies that consistently win on value, not just on price, are those whose ACS score genuinely reflects operational excellence, and who can evidence that to a sophisticated client during due diligence.

For growing security businesses, ACS is both a licence to tender and a framework for building the operational discipline that makes growth sustainable.

Key Takeaways

• ACS accreditation is a voluntary but commercially essential quality standard for UK security companies operating in public sector and corporate markets
• The ACS standard has seven criteria: strategy, service delivery, commercial relationship management, financial management, resource management, people, and leadership
• SIA licence records need to stand up to sampling: digital audit trails are far easier to evidence than spreadsheet records
• ACS is an ongoing improvement framework, not a one-off certification: companies that use it as a management tool outperform those that treat it as a compliance exercise
• Technology that automates compliance logging as a by-product of operations significantly reduces the evidence-gathering burden at assessment time

Managing ACS compliance across a growing security workforce? See how TacDesk’s Compliance module scores your readiness across the ACS criteria and keeps the evidence trail together.