Deemed Contractors

Key facts

A deemed contractor is a business whose main activity is not construction but which spends over £3 million on construction operations in any 12-month period.
Examples include retailers, hotel chains, NHS trusts, and local authorities that commission significant construction or refurbishment work.
Once the £3 million threshold is crossed, the business must register for CIS and operate the scheme for all future subcontractor payments.
Deemed contractors remain under CIS obligations indefinitely — there is no automatic de-registration if spending drops.
Government departments and local authorities are always deemed contractors, regardless of spending levels.

What Is a Deemed Contractor?

Most CIS contractors are construction businesses by trade. However, CIS also applies to organisations whose main activity is not construction but which spend significant amounts on construction work. These are known as deemed contractors.^[1]

The rationale is straightforward: if a business is paying large sums to subcontractors for construction operations, HMRC wants to ensure that tax is collected at source — regardless of what the business’s core activity is.

The £3 Million Threshold

A business becomes a deemed contractor when its cumulative spending on construction operations exceeds £3 million over any rolling 12-month period.^[3]

Key points about the threshold:

It is a rolling 12-month test, not aligned to the tax year or financial year
It includes payments to subcontractors for construction work, including VAT
It covers all construction operations across all sites and projects
The threshold applies to the business as a whole, not individual projects
Once breached, the business becomes a deemed contractor and must register for CIS

Example: A national hotel chain spends £2.5 million refurbishing hotels in the first nine months of the year, then awards a £600,000 contract for a new hotel extension. The total (£3.1 million) exceeds the threshold, so the chain becomes a deemed contractor and must register for CIS.

Automatic Deemed Contractors

Some organisations are deemed contractors automatically, with no spending threshold:^[3]

Government departments (e.g. Ministry of Defence, HMRC itself)
Local authorities (county councils, district councils, unitary authorities)
NHS trusts and health authorities
Housing associations (registered social landlords)
Development agencies and corporations

These bodies must operate CIS on any construction payments to subcontractors, even for small amounts.

Examples of Deemed Contractors

Type of Business	Scenario	CIS Status
Supermarket chain	Spends £4m per year fitting out and refurbishing stores	Deemed contractor (over £3m)
University	Commissions a £5m new teaching block	Deemed contractor (over £3m)
Manufacturing company	Builds a £3.5m factory extension	Deemed contractor (over £3m)
Small retailer	Spends £50,000 refurbishing a shop	Not a deemed contractor (under £3m)
Local council	Pays £10,000 to a builder for minor repairs	Deemed contractor (automatic — no threshold)

Deemed Contractor Obligations

Once triggered, deemed contractors have the same obligations as regular CIS contractors:^[2]

Register with HMRC as a CIS contractor
Verify every subcontractor before the first payment under each contract
Make CIS deductions at the rate specified by HMRC (0%, 20%, or 30%)
Provide payment and deduction statements to each subcontractor
File monthly CIS returns (form CIS300) by the 19th of the following month
Pay deductions to HMRC by the 19th (postal) or 22nd (electronic) of the following month
Keep records for at least 3 years after the end of the tax year

Tip: If your business is approaching the £3 million threshold, start preparing for CIS obligations in advance. Registering, setting up verification processes, and updating your accounts system takes time — you do not want to be caught out when the threshold is crossed.

Monitoring and De-Registration

Once a business becomes a deemed contractor, there is no automatic de-registration if spending subsequently drops below £3 million. The business must continue operating CIS unless HMRC agrees to remove the deemed contractor status.^[3]

To apply for de-registration, you would need to demonstrate to HMRC that:

Your construction spending has fallen well below the £3 million threshold
You do not expect it to reach that level again in the foreseeable future
The original construction projects or programmes have been completed

In practice, many deemed contractors find it simpler to remain registered, especially if there is any possibility of future construction spending.

Common Pitfalls

Not realising the threshold has been reached — construction spending can accumulate across multiple departments and projects. Centralised tracking is essential.
Confusing the threshold with annual spending — it is a rolling 12-month period, not aligned to your financial year.
Ignoring VAT — the £3 million threshold includes VAT. A £2.6 million project plus 20% VAT is £3.12 million.
Forgetting about maintenance contracts — ongoing maintenance and repair of buildings counts as construction expenditure.

Frequently Asked Questions

What is a deemed contractor?

A deemed contractor is a business or organisation whose main activity is not construction but that must operate CIS because its construction spending exceeds £3 million in a rolling 12-month period. Government bodies and local authorities are deemed contractors automatically, without a spending threshold.

How is the £3 million threshold calculated?

The threshold is based on your cumulative spending on construction operations over any rolling 12-month period. It includes all payments to subcontractors for construction work, including VAT. If you reach £3 million at any point, you become a deemed contractor.

What happens if my spending drops below £3 million?

Once you become a deemed contractor, you remain one. There is no automatic de-registration if your spending drops below the threshold in subsequent years. You must continue to operate CIS unless you apply to HMRC and they agree to remove the deemed contractor status.

Do deemed contractors have the same obligations as regular CIS contractors?

Yes. Deemed contractors must register for CIS, verify subcontractors, make deductions at the appropriate rate, file monthly CIS returns, and pay deductions to HMRC — exactly the same obligations as any other CIS contractor.

Sources

Construction Industry Scheme (CIS) — GOV.UK
What you must do as a CIS contractor — GOV.UK
CIS: deemed contractors (CISR12020) — HMRC
Finance Act 2004, section 59 – Contractors — legislation.gov.uk