SIA approved contractors sub-contracting outside of the ACS
Source: gov.uk (2025-11-06)

Sub-contracting to a company that is not an SIA approved contractor: what the rules are and how you ask for permission.

Unless we have given you permission to do otherwise, you must only sub-contract to SIA approved contractors. Your customers have contracted an SIA approved contractor and will therefore expect the service they receive to be from an approved contractor.

In exceptional circumstances, we may allow you to sub-contract to a company we have not approved. You need our permission to do this and your customer must also agree to it. Any permission we grant will be for a limited time – usually no longer than 3 months.

How to ask for permission

Fill out the Application to sub-contract outside of the ACS form (https://assets.publishing.service.gov.uk/media/690c7d8adad669f061d46b18/sia-subcontracting-form.odt) (ODT, 31.5 KB).

You must fill in all fields marked with an asterisk (*). We will reject any form in which any of these fields are left blank.

Upload the form to your SIA online business account. Select ‘Help’, then select ‘Other’ as the category. Enter “sub-contractor request” as the text of your message.

Ideally, you should ask us for permission before you sub-contract the work. If this is not possible then you must do so within 5 working days after deployment.

How we make our decision

We review each application individually. We will consider your specific situation.

We will only give you permission if we agree that your circumstances are exceptional.

We will also consider:
- your track history of following ACS rules
- your efforts to avoid using a company we have not approved
- whether you could have prevented the situation by acting earlier
- any potential risk to public safety or the reputation of our approved contractor scheme
- the due diligence and quality checks you have done to confirm the sub-contractor meets the required ACS standard
- how you will align the sub-contracted service with ACS requirements (your ‘sub-contractor plan’)
We will try to reach a decision within 5 working days.

What we mean by ‘ACS requirements’

When we refer to you aligning the sub-contracted service with ACS requirements, these are the specific points we are referring to:
- Indicator 1.1.2 – key stakeholders are aware of the organisation’s overall approach to business
- Indicator 1.2.1 – critical success factors have been clearly identified and internal measures are in place to monitor progress towards achievement
- Indicator 2.2.1 – there is a current and effective plan to ensure continuity of service delivery
- Indicator 2.4.1 – use of sub-contractors is agreed with customers and subject to defined quality assurance procedures
- Indicator 2.4.2 – effective customer and consumer performance indicators and service level agreements have been established
- Indicator 2.6.1 – the organisation regularly reviews performance against service level agreements and/or key customer performance indicators
- Indicator 3.1.1 – effective purchasing procedures are implemented
- Indicator 3.5.1 – the organisation regularly reviews performance against responses from customer opinion gathering
- Indicator 4.2.1 – clear and effective management of the payroll can be evidenced
- Indicator 4.2.4 – there is sufficient insurance to cover contractual requirements
After we have reached our decision

We will tell you in writing whether we give you permission. If we do, we will explain the conditions of our permission and the date it expires.

If we do not give you permission, we will explain why.

You can appeal our decision if we do not give you permission. Contact us through your business account to ask for an independent review.

What counts as exceptional circumstances?

Exceptional circumstances are when your only option is to use a contractor we have not approved. This is usually when you have an urgent need and no SIA-approved contractor is available.

Some examples are:
- you need a specialised service and you cannot find an SIA-approved contractor who offers it
- you have a short-term security demand that your company cannot satisfy on its own (such as a festival or major event) and you cannot find enough SIA-approved contractors to cover it
- you need security services urgently for a situation where people’s health and safety is at risk
Sub-contracting versus use of labour

‘Sub-contracting’ is different from ‘use of labour’. ‘Use of labour’ refers to hiring temporary workers. You do not need our permission to do this. Know the difference between sub-contracting and use of labour (https://www.gov.uk/guidance/know-the-difference-between-sub-contracting-and-use-of-labour).