Last updated: 14 October 2026
Can you use a scanned signature on form 64-8 to authorise an agent for CIS?
For most taxes, including CIS, you no longer need to rely on a signed paper form. HMRC’s preferred route is online authorisation: your accountant sends a request through their agent services account, or uses HMRC’s online agent authorisation, and you approve it with your own Government Gateway login. The paper 64-8 form still exists, with a CIS section, and can authorise an agent to deal with HMRC by phone and in writing. Whether a scanned or electronic signature is accepted on it depends on HMRC’s current guidance, so check before relying on one. The online route avoids the question entirely.
Ways to authorise an agent
| Method | Used for |
| Agent services account request (digital handshake) | Self Assessment, VAT, MTD for Income Tax and other services listed by HMRC |
| Online agent authorisation | PAYE, CIS, corporation tax and others |
| Client adds agent in their business tax account | CIS and some other services |
| Form 64-8 | Phone and written dealings; some taxes where online routes aren’t available |
Why it matters for CIS
Contractors must verify subcontractors, file monthly CIS returns by the 19th, and pay deductions by the 22nd if paying electronically. Subcontractors may want an agent to check their CIS deductions and claim refunds. Without authorisation, HMRC won’t discuss your account with your accountant, which can delay returns and refunds.
Example
A roofing contractor appoints an accountant in October 2026 to file its monthly CIS returns. The accountant requests authorisation online. The director receives an authorisation code by post at the company’s registered address, gives it to the accountant within 30 days, and the accountant can then file the next return. If the director misses the code, a new request is needed.
Practical tips
- Make sure your address with HMRC is up to date, as codes are posted
- Act on authorisation requests promptly, as links and codes expire
- Check which taxes the agent is authorised for: CIS, PAYE and corporation tax are separate
- Remove old agents when you change accountant
Subcontractor refunds
Limited company subcontractors reclaim CIS deductions through the company’s monthly PAYE submissions (EPS), not Self Assessment. Sole traders claim through their tax return. Having your agent authorised for the right taxes speeds up these refunds.
Security
Never share your Government Gateway password with an agent. Authorisation lets them act for you through their own login. If someone asks for your password, treat it as a warning sign.
Changing accountants
When you move to a new accountant, the new firm requests its own authorisation. The old agent’s access doesn’t pass across. Until the new one is in place, keep filing on time yourself or ask the old firm to file the next return, so you don’t get a late CIS return penalty, which starts at £100.
Frequently asked questions
Does HMRC accept emailed 64-8 forms?
Check HMRC’s current guidance; online authorisation is quicker.
How long does authorisation take?
Online, often days; post-based codes take longer.
Can one agent act for CIS and VAT?
Yes, with separate authorisations.
Do I need to authorise again each year?
No, it continues until removed.
Related: registering for CIS for carpet fitting, CIS gross payment status and CIS for consultancies.
Talk to Accotax
Want this handled for you? Our team at Accotax can help with authorising an agent for CIS. See our CIS accountants service, or contact us for a free, no-obligation quote.
This page is general guidance based on HMRC rules for the 2026/27 tax year, checked against gov.uk on 14 October 2026. It is not personal advice, so speak to an accountant about your own situation.
