HMRC Security Checks: Why your CIS refund is delayed in 2026

A delayed CIS refund isn't just a nuisance; it's a cash flow crisis for your business. Discover why HMRC security checks are increasing and how to prevent your money from being held for months.

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CIS Tax · 5 min read ·

HMRC Security Checks: Why your CIS refund is delayed in 2026
CIS Refund Delayed in 2026? Here's Exactly Why HMRC Is Holding Your Money
Construction Industry Scheme · 2026 Update

CIS Refund Delayed in 2026?
Here's Exactly Why HMRC
Is Holding Your Money

You're owed thousands of pounds in overpaid CIS tax — and it's still sitting with HMRC. Here's what's really going on, and what you can do right now.

Updated March 2026  ·  5 min read
3–6 Months typical wait
once under review
21+ Months — worst-case
delays reported
23 min Average HMRC
call wait time

Why Your CIS Refund Is Taking So Long Right Now

HMRC doesn't delay refunds randomly. When your payment is held up, there's always a reason — and in 2026, the landscape is worse than it's been in years.

A combination of structural problems has stacked up behind the scenes. HMRC staff carried out industrial action from December 2024 through June 2025, creating a backlog that is still being worked through. Accountants on professional forums are reporting clients who submitted in April 2025 and were told not to expect a response until March 2026 — nearly 12 months later.

On top of that, staff shortages, the rollout of Making Tax Digital for Income Tax (which begins in April 2026), and enhanced fraud prevention checks are all slowing the system down.

Real example: One accountant reported that HMRC made a partial refund in August 2025, then sent a CIS reconciliation by post — and estimated the remainder wouldn't be processed until 22 March 2026. "That will then be nearly 12 months after the original claim," they wrote on AccountingWEB.

The Most Common Reasons Your Specific Refund Is Stuck

Even within a delayed system, some returns move through quickly. Others get flagged for manual review. Here's what triggers that check:

  • Mismatched CIS figures. Your declared income or CIS tax suffered doesn't match what your contractors reported to HMRC on their monthly returns. This is the single most common cause.
  • Unusual expense claims. High mileage, materials or tool costs without clear supporting evidence — especially invoices and receipts that align with your bank statements.
  • Small data errors. An outdated address, incorrect UTR, or bank details that don't match HMRC's records can freeze a refund completely.
  • Outstanding liabilities. HMRC will offset any unpaid tax, penalties or PAYE debt against your refund before releasing the balance.
  • First-time claimants. If you've never claimed a CIS refund before, HMRC routinely runs additional identity and registration checks.
  • Large refund amounts. Claims above typical thresholds are more likely to be selected for compliance review regardless of accuracy.
2026 context: Making Tax Digital

From April 2026, HMRC is also removing its free online service for filing company tax returns, requiring businesses to use commercial software. This transition is adding extra administrative pressure across HMRC departments — and contributing to the backlog affecting CIS processing.

Realistic Timelines: What to Actually Expect

Best case
2–6 weeks

A clean, accurate return with no discrepancies and no outstanding liabilities. Increasingly rare in 2026 due to system-wide backlogs.

Standard in 2026
3–6 months

Most CIS refund claims submitted after April 2025. HMRC has acknowledged the backlog and says additional staff are being allocated.

Under compliance review
6–12+ months

If your return is flagged, or if you don't respond quickly to information requests, you could be waiting well into 2027.

Worst cases reported
Up to 21 months

HMRC has acknowledged complaints on social media about 21-month waits. These are extreme cases but are no longer unheard of.

Important
If your Corporation Tax payment falls due while you're still waiting for your CIS refund, HMRC will deduct the CT bill from your refund before releasing the balance — even if you didn't request this. Call the HMRC debt helpline to explain the situation and avoid late payment penalties.

What You Can Do Right Now to Speed Things Up

The subcontractors who get paid fastest are those with organised documentation who respond to HMRC immediately. Work through this list today:

Your CIS Refund Action Checklist
Collect every CIS Payment & Deduction Statement from all contractors. Cross-check the totals against what you declared on your Self Assessment.
Log into your Personal Tax Account and check your message inbox for any open queries, verification requests, or letters you may have missed.
Use HMRC's "Where's My Reply" tool to check the current status and the date HMRC is working to — before calling.
Verify that your UTR, address, National Insurance number and bank details are all up to date with HMRC. A single mismatch is enough to freeze a payment.
Prepare proper evidence for every expense you've claimed: dated invoices, mileage logs with locations and purposes, receipts matched to bank statement entries.
If HMRC has written to you requesting information, respond immediately and completely. Each round of back-and-forth adds 2–3 weeks to your wait.
Keep a written record of every interaction with HMRC — date, time, adviser name, and what was said. This is essential if you need to escalate.
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Frequently Asked Questions

How long does a CIS refund take in 2026?

In ideal conditions — a clean return with no discrepancies — you're looking at 2–6 weeks. In practice, most claims submitted in 2025–2026 are taking 3–6 months due to HMRC's ongoing backlog. If your return is selected for a compliance check, 6–12 months is realistic. The absolute worst cases reported have exceeded 21 months.

Why is there a bigger backlog in 2026 specifically?

Three factors collided: HMRC staff carried out industrial action from December 2024 to June 2025, leaving a large backlog of unprocessed claims. That coincided with staff shortages from post-pandemic restructuring, and the simultaneous rollout of Making Tax Digital for Income Tax from April 2026. The system was already under pressure before any individual return entered the queue.

What is a HMRC compliance check on a CIS refund?

It's a manual review triggered when something in your return doesn't match HMRC's records. The most common triggers are mismatched CIS deduction figures (where a contractor's monthly return to HMRC doesn't align with what you declared) and expense claims that fall outside normal patterns for your type of work. During a compliance check, HMRC may ask for invoices, mileage records, bank statements, or contractor correspondence.

Can HMRC reduce or withhold my refund?

Yes, in two ways. First, if you can't provide adequate evidence for expenses you've claimed, those amounts can be disallowed — reducing your refund. Second, HMRC will automatically offset any outstanding tax debt, penalties, or unpaid PAYE against your refund before releasing the balance. You won't necessarily be warned in advance.

Can I call HMRC to chase my refund?

You can, but it's rarely productive during the current backlog. Average call wait times are over 23 minutes, and agents frequently refer callers back to the "Where's My Reply" online tool. Only call if the expected processing date shown in the tool has passed, or if you've received a letter requesting action. Having an accountant or tax agent contact HMRC on your behalf via the Agent Helpline often gets faster results.

What if my Corporation Tax is due while I'm waiting for my CIS refund?

Contact the HMRC debt helpline and explain the situation in writing. HMRC has acknowledged it will deduct any CT liability from your CIS refund before releasing the balance, even if you didn't request this. If you receive a demand for Corporation Tax while waiting, keep records of all correspondence explaining the refund is in process — this protects you from late payment penalties in most cases.

Is it worth applying for gross payment status?

For some subcontractors, yes. If HMRC's delays are creating serious cash flow problems, applying for Gross Payment Status means contractors pay you in full without deducting CIS tax — eliminating the refund process entirely. You'll need to pass HMRC's compliance and turnover tests. It's worth discussing with a tax professional if you're consistently receiving large CIS refunds each year.