CIS Inactivity Periods: When To Notify HMRC And Avoid Penalties
- Atlas Tax
- Jun 9
- 13 min read
CIS Inactivity Periods: When to Notify HMRC and Avoid Penalties
For contractors registered under the Construction Industry Scheme, monthly returns are not optional , they are a legal obligation that runs regardless of whether any payments to subcontractors were actually made in a given month. This is the detail that catches many small and medium-sized construction businesses out: the obligation to file does not disappear simply because work was quiet, a project was delayed, or a business temporarily stopped using subcontractors.
The result is a steady stream of late-filing penalties for contractors who assumed there was nothing to report and therefore nothing to submit. Understanding when and how to notify HMRC of an inactivity period is one of the simpler but most practically important compliance steps a construction contractor can take.
How the CIS Monthly Return Works
As a contractor, you must send a monthly return to HMRC by the 19th of each month for the previous tax month. The tax month runs from the 6th of one month to the 5th of the next. So the return for the month ending 5 May is due by 19 May.
You can submit CIS returns online through HMRC's CIS online service or use commercial CIS payroll software. If you fail to file a monthly return by the 19th of the month, HMRC will charge a penalty automatically.
The penalty structure escalates with delay:
● One day late: £100 automatic penalty
● Two months late: a further £200
● Six months late: £300 or 5% of the CIS deductions that should have been reported, whichever is higher
● Twelve months late: a further £300 or 5% of the CIS deductions, whichever is higher
For a contractor who goes quiet for several months and fails to file returns, these penalties compound quickly. A contractor who misses six consecutive monthly returns , for example, during a slow period over winter , could face penalties totalling over £3,000 before any deductions have even been considered.
The Inactivity Notification: What It Is and Why It Matters
The solution for a contractor who knows in advance that they will not be making any payments to subcontractors in a forthcoming period is to notify HMRC of an inactivity period. This is sometimes called an inactivity declaration or a nil return, though the inactivity notification mechanism is more specific.
If you're a contractor and you know you won't be making payments to any subcontractors for a period of time, you can tell HMRC you want to stop filing monthly returns for a period. HMRC will then not expect any returns for up to six months.
This six-month inactivity window means the contractor does not need to file monthly nil returns throughout that period , removing the compliance obligation and the associated penalty risk. The notification is effectively telling HMRC: no subcontractors will be paid for the next six months, so there will be no returns to submit.
The notification can be made by telephone, through the CIS online service, or by the contractor's accountant or agent. The key requirement is that it is made before the next return is due , not after the period has passed.
What Happens When Activity Resumes
When you restart CIS work and begin paying subcontractors again, you must tell HMRC and restart your monthly returns from the date you start paying subcontractors again.
The obligation to restart returns is triggered by the first payment to a subcontractor after the inactivity period , not by the formal end of the six-month window. If a contractor notified an inactivity period of six months but then takes on a subcontractor after three months, they must restart their monthly CIS returns from the month of that first payment. Waiting until the six-month period expires before resuming returns would leave the interim months unfiled and create penalty exposure.
The Practical Risk: When Notification Is Not Made
The pattern that generates the most CIS penalties involves contractors who experience genuine quiet periods , a lost contract, a seasonal slowdown, difficulty finding reliable subcontractors , and who simply stop filing returns, intending to resume when work picks up.
Without an inactivity notification, HMRC continues to expect monthly returns throughout the quiet period. The automatic penalty system issues charges after each missed deadline. By the time work resumes and the contractor or their accountant realises that unfiled returns have accumulated, the penalty total can be substantial.
A contractor who had no subcontractor activity from October to April , seven months , and made no returns and no inactivity notification would face:
Month | Days Late | Penalty |
October return (due 19 Nov) | 60+ days | £100 minimum |
November return | 60+ days | £100 minimum |
December return | 60+ days | £100 minimum |
January return | 60+ days | £100 minimum |
February return | 60+ days | £100 minimum |
March return | 60+ days | £100 minimum |
April return | 60+ days | £100 minimum |
That is a minimum of £700 in automatic penalties before the escalating charges at two, six, and twelve months apply to the earlier returns. Where returns remain unfiled for six months, the £300 penalty or 5% of deductions applies , and for a medium-sized contractor, 5% of typical deductions easily exceeds £300.
Appealing Penalties: The Reasonable Excuse Standard
HMRC's penalty system is automated, and penalties are issued without considering the contractor's circumstances. The mechanism for challenging penalties is the formal appeal process, which requires a reasonable excuse for the late filing.
You can appeal against a late filing penalty if you have a reasonable excuse for missing the deadline. What counts as a reasonable excuse is assessed case by case and depends on the specific circumstances.
A contractor who was unaware of the CIS monthly return obligation may have a reasonable excuse argument, but it is not strong where they have been registered as a contractor and had prior dealings with HMRC. HMRC's view is generally that registered contractors are expected to understand their legal obligations.
More compelling reasonable excuse arguments include: serious illness of the contractor or a key person responsible for compliance; a death in the family at a critical time; HMRC technical failure that prevented online submission; or genuinely exceptional circumstances. An administrative oversight , forgetting to notify an inactivity period , is unlikely to succeed as a standalone excuse without some additional mitigating factor.
The most effective approach is prevention: making the inactivity notification before the quiet period begins, rather than appealing penalties after they have been issued.
Occasional Use of Subcontractors: A Different Compliance Risk
Not every contractor who encounters a quiet period is a large firm with a well-staffed accounts department. Many CIS-registered contractors are sole traders or directors of small limited companies who use subcontractors intermittently , taking on specialist trades for specific projects and working alone on smaller jobs.
For this group, the monthly return filing obligation can feel disproportionate to the scale of their operations. The obligation exists nonetheless, and the penalty consequences are the same regardless of company size.
The distinction between a contractor who is consistently using subcontractors and one who uses them only occasionally is relevant to whether deregistration from CIS as a contractor might be more appropriate than using the inactivity notification mechanism for repeated quiet periods.
You must register as a CIS contractor if you pay subcontractors for construction work. If you are genuinely not going to use any subcontractors, it is possible to deregister as a contractor.
Deregistration removes the monthly return obligation entirely. Re-registering when work picks up and subcontractors are needed again is possible, though the process takes some time, and making payments to subcontractors without first completing re-registration and verifying those subcontractors through CIS would itself be a compliance failure.
For a small contractor who uses subcontractors only once or twice a year, the cost-benefit of remaining registered , with the obligation to manage monthly returns or inactivity notifications throughout the year , versus deregistering and re-registering as needed deserves genuine consideration. The administrative cost of managing an ongoing CIS registration that sits dormant for most of the year can outweigh the convenience of having it available.
The Contractor-Subcontractor Dual Role
Many construction businesses operate simultaneously as contractors (paying subcontractors) and subcontractors (being paid by other contractors for their own work). The inactivity notification mechanism applies to the contractor role , the obligation to file monthly returns when paying subcontractors.
Your status as a subcontractor receiving CIS deductions from other contractors is entirely separate from your own obligations as a contractor making CIS deductions from your subcontractors. An inactivity period notification for your contractor obligations does not affect the CIS deductions that other contractors are required to make from payments to you.
This dual status is a source of confusion in CIS compliance. A specialist subcontractor who also occasionally engages their own subcontractors for larger projects must manage their compliance in both roles. When they are quiet on the contractor side, the inactivity notification addresses their return-filing obligation. When they continue to receive payments from other contractors, those deductions continue normally , the subcontractor role is unaffected by the contractor role inactivity notification.
For businesses in this dual role, maintaining clarity between the two sets of records and obligations is important. A CIS return relates to payments made as a contractor , it is not a return of amounts received as a subcontractor, which are handled through the self-employed or company tax return at year end.
The Treatment of Materials: What Goes on the Return
For months where a contractor does make payments to subcontractors, the CIS monthly return must distinguish between the labour element of each payment and the materials element. CIS deductions are applied only to the labour element , materials are excluded from the withholding calculation.
CIS deductions apply to the labour element of payments to subcontractors. Materials supplied by the subcontractor as part of the work are excluded from the CIS deduction calculation.
This matters for understanding why a return is not always simply nil even when a contractor's subcontractors are charging primarily for materials. If a subcontractor invoices £10,000 of which £7,000 is materials and £3,000 is labour, the CIS deduction applies only to the £3,000 labour element. Where the subcontractor holds gross payment status, no deduction is made at all.
The distinction between labour and materials is one of the more consistently challenging CIS compliance areas, because invoices from subcontractors do not always present the split clearly. HMRC's guidance requires contractors to make a reasonable determination of the split , and to apply the deduction accordingly , rather than simply deducting on the full invoice value.
Gross Payment Status and Its Effect on Returns
Subcontractors with gross payment status are paid in full without any CIS deduction. Contractors must still verify a subcontractor's gross payment status through HMRC's online service before making a gross payment, and must still include them on the monthly CIS return , even though no deduction has been made.
This is another compliance trap. A contractor who works only with gross payment status subcontractors still needs to file monthly returns recording the payments made , the returns are not nil simply because no deductions were applied. Failing to file because "there were no deductions to report" conflates the absence of withheld tax with the absence of a filing obligation. The obligation exists whenever payments are made to subcontractors, regardless of their deduction status.
For a contractor filing a period of inactivity, the threshold for notification is genuinely no subcontractor payments at all , not simply no deductions applied.
Key Compliance Actions: A Summary
The practical compliance position for contractors managing CIS through quiet periods can be distilled into a clear decision framework:
If you know no subcontractor payments will be made for a period of up to six months: Notify HMRC of an inactivity period before the first missed return deadline. This suspends the monthly filing obligation for up to six months and prevents automatic penalties.
If the quiet period extends beyond six months: A further notification will be needed. The six-month inactivity window does not automatically renew , contractors who remain inactive beyond the initial notification period should contact HMRC to extend the arrangement.
If subcontractor payments resume during a notified inactivity period: Notify HMRC and restart monthly returns from the month the first payment is made. Do not wait for the inactivity period to formally expire.
If the business consistently uses subcontractors only once or twice a year: Consider whether deregistering as a CIS contractor and re-registering when needed is more practical than managing ongoing inactivity notifications throughout the year.
If penalties have already accumulated for unfiled returns: File all outstanding returns as soon as possible to stop further penalties from accruing. Appeal where there is a genuine reasonable excuse, supported by evidence. Make the inactivity notification going forward to prevent recurrence.
Key Takeaways
● CIS contractors must file a monthly return by the 19th of each month, covering payments made to subcontractors in the preceding tax month. The obligation applies regardless of whether any deductions were made.
● Contractors who know they will not be paying subcontractors can notify HMRC of an inactivity period for up to six months, suspending the monthly return obligation for that period. The notification must be made before the missed returns become due.
● Penalties for late CIS returns start at £100 per missed return and escalate to £300 or 5% of deductions (whichever is higher) for returns outstanding at six months. Multiple missed returns compound rapidly.
● The inactivity notification applies only to the contractor role. Subcontractor obligations , including receipt of CIS deductions from other contractors , continue unaffected.
● Subcontractors with gross payment status must still be included on the monthly return, even though no deduction is applied. The return obligation arises from payments made, not from deductions withheld.
● For contractors who use subcontractors only occasionally, deregistration and re-registration when needed may be more appropriate than managing repeated inactivity notification periods throughout the year.
● Appeals against CIS penalties require a reasonable excuse. Administrative oversight is unlikely to succeed on its own , proactive notification is a more reliable approach than retrospective penalty mitigation.
FAQs
Q1: What exactly triggers the need to notify HMRC about inactivity in the CIS scheme, and how does it differ from simply filing a nil return?
Well, in my experience advising construction clients across the UK, many contractors get caught out here. An inactivity notification (or request) is your way of telling HMRC you’ve temporarily stopped using subcontractors and don’t expect payments in the foreseeable future, typically for up to six months. This suspends your monthly filing obligation entirely. A nil return, on the other hand, is still a formal submission showing zero payments for that specific month. The inactivity route saves hassle during genuine quiet periods, like between major projects, but you must use the CIS online service or contact HMRC properly. Get this wrong, and you risk automatic penalties even with no money changing hands.
Q2: How do I actually make an inactivity request, and what’s the best timing to avoid any gaps?
It’s straightforward but timing matters. You can usually make the request when filing a nil return via the CIS online service, or by phone/post if needed. Aim to do it before or during a quiet spell, ideally with some buffer. I’ve seen clients in Manchester who waited until after the deadline and ended up with a £100 penalty before the inactivity kicked in. Once approved, it starts covering the relevant periods, but always confirm the exact dates with HMRC.
Q3: Can a deemed contractor get a longer inactivity period than the standard six months?
Yes, and this is a useful provision many overlook. Deemed contractors (those exceeding the £3m construction spend threshold in a rolling 12 months) can contact HMRC directly to request an extended period if they genuinely don’t expect payments for longer. In practice, I’ve helped property development clients secure this when winding down a phase. It’s not automatic, so prepare clear reasons and evidence of your situation.
Q4: What happens if I start using subcontractors again during an approved inactivity period?
You must notify HMRC straight away and file a monthly return for that period showing the payments. The inactivity ends immediately upon filing a return with payments. One client of mine in Birmingham forgot this and assumed the old period would roll, it led to compliance headaches. Treat it as a reset and stay proactive to keep things clean.
Q5: My business has seasonal work with predictable winter downtime, is inactivity notification the right approach every year?
Absolutely, and it’s a smart way to stay compliant without unnecessary admin. For seasonal trades like roofing or groundwork in colder regions, pre-notifying for those expected quiet months works well. Renew it every six months as needed. Just ensure your records show the genuine temporary nature, HMRC can review patterns over time.
Q6: I received a late filing penalty even though I thought my account was inactive, what’s the likely cause and fix?
This is a common pitfall. Often, the inactivity wasn’t properly set, there were outstanding prior returns, or the reactivation wasn’t handled correctly. First, check your CIS online account for the status. File any missing returns promptly, then appeal the penalty with evidence of your request and reasonable steps taken. In my 15+ years, clear communication and records usually resolve these favourably if acted on quickly.
Q7: Does inactivity notification affect my subcontractors’ records or their ability to claim tax credits?
No direct impact, as long as any prior payments were correctly reported. Subcontractors rely on your accurate monthly returns for their own tax affairs. During true inactivity, there are simply no new deductions to report. I always advise clients to issue final statements to subs before quiet periods to avoid disputes later.
Q8: What’s the difference in approach for a small builder versus a larger contractor with multiple sites?
Smaller sole traders or partnerships often benefit most from inactivity during gaps between jobs, keeping things simple. Larger contractors with ongoing obligations might use it selectively for specific dormant schemes. The rules are the same, but larger operations need robust systems, I’ve seen firms use accounting software alerts to flag when inactivity needs renewing across projects.
Q9: Can I make an inactivity request retrospectively, and what are the risks?
Generally, no, it’s proactive. Trying to backdate often fails and leaves you exposed to penalties for the intervening months. Always notify in advance or at the time of a nil return. One Leeds-based client learned this the hard way after a delayed project start; proactive planning saved them significant stress and costs later.
Q10: How often can I renew an inactivity period, and is there a limit?
You can renew it at the end of each six-month period as long as the situation remains genuine. There’s no strict overall limit, but repeated long inactivity might prompt HMRC to question if you should deregister instead. For deemed contractors, longer single periods are possible. Keep your reasons consistent and documented.
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