While charities in the UK enjoy significant tax exemptions, they are not automatically exempt from filing tax returns as many people (erroneously) believe.
Depending on its constitutional type, a charity must submit either a Corporation Tax Return (“CT600”) or a Trust and Estates Tax Return, whenever HMRC issues a notice to deliver one - even if no tax is ultimately due.
Charities that may have to complete a CT600
CT600s apply to charitable companies, CIOs and unincorporated associations, particularly where the charity has taxable income like non‑primary‑purpose trading or rental income that falls outside charitable exemptions.
The key deadlines are in line with those for all companies:
- The Corporation Tax payment is due 9 months and 1 day after the end of the accounting period
- The CT600 return filing deadline is 12 months after the accounting period end
Missing these deadlines can result in penalties for late filing – which doubled for returns filed late after April 2026 to an initial £200. Further penalties are issued for prolonged delays. Late payment of tax liabilities will also result in interest being charged.
Charitable trusts and tax
Charitable trusts follow different rules. Instead of a CT600 return, charitable trusts must complete a “Trust and Estate Self Assessment tax return” if they have income that does not qualify for charitable tax relief, or whenever HMRC requires one. A “trust” is classified as such if established by a trust deed, regardless of what its official name is. The deadlines are the same as the Self Assessment timetable for personal tax returns, and late filing can also trigger penalties.
The importance of responding
As you can see, the requirements are more stringent than you might think for charities that in most cases do not pay any corporation or income tax. If you do receive a request for a return please do not ignore it! HMRC request them for good reason and insist on their completion.
In the past, there was the option for some charities to prepare and file their own return via the government gateway. However, following the closure of the corporation tax filing service on the gateway in April 2026, charities can no longer file these returns internally – as all corporation tax returns must now be filed using professional software. Please contact your accountant or tax adviser for assistance at the earliest opportunity.
We at CT have specialist tax staff that deal almost wholly with charity tax returns. For further guidance, please get in touch with Conall Boyle at Conall.Boyle@ct.me.
Below we have set out a comparison table showing the tax‑return requirements for charitable companies / SCIOs / CIOs, unincorporated charitable associations, and charitable trusts.
Comparison table: tax return requirements for different types of charities (UK)
| Charity type | When a tax return must be submitted | Type of return required | Relevant deadlines | Key notes |
| Charitable Companies (registered with Companies House) | Must file a Corporation Tax Return (CT600) whenever HMRC issues a notice, even if no tax is due. | CT600 (Corporation Tax Return) | Payment deadline: 9 months + 1 day after accounting period end. Filing deadline: 12 months after accounting period end. | Must report any taxable income (e.g., non‑primary‑purpose trading, non‑exempt investment income). Penalties apply for late filing. |
(and CIOs in England and Wales) | Must file CT600 if HMRC issues a notice, even if claiming full exemptions. | CT600 (Corporation Tax Return) | As for charitable companies: payment due at 9 months + 1 day; filing due at 12 months. | SCIOs may have to file even with no Corporation Tax liability. HMRC often requests returns to verify eligibility for exemptions. |
| Unincorporated Charitable Associations | Must file CT600 if HMRC issues a notice or if they have taxable (non‑exempt) income. | CT600 (Corporation Tax Return) | Same as company deadlines: pay at 9 months + 1 day; file at 12 months after period end. | Includes groups formed by constitution (not trusts). Must include charity-specific supplementary pages. |
| Charitable Trusts | Must file a tax return if they have income not eligible for charitable tax relief or if HMRC instructs them to submit one. | Trust & Estate Self Assessment Tax Return (not CT600) | Deadlines follow Self Assessment rules (e.g., typically 31 January for online filing). | A charity is classed as a trust if created by a trust deed (or will). |