CT600J is the supplementary page of the Company Tax Return on which a company reports the Scheme Reference Numbers of tax avoidance schemes it has used. It belongs to the Disclosure of Tax Avoidance Schemes (DOTAS) rules. Most companies never need it. This guide explains when you do, how to complete the page in Tax Optimiser, and what every box from J1 to J50A means.
When a company needs a CT600J
Under DOTAS, the promoter of certain tax arrangements must tell HMRC about them. HMRC then issues an eight-digit Scheme Reference Number (SRN), and the promoter passes it on to each client who uses the scheme, normally on form AAG6.
File a CT600J, and tick boxes 65 and 140 on the CT600, if the company:
- has been given a Scheme Reference Number for arrangements it is party to; and
- expects a Corporation Tax advantage from those arrangements in the return period.
The number has to be reported on the return for every accounting period in which an advantage is expected, not only the first. A company that does not report a number it has been given can be charged a penalty for each scheme.
Having an SRN does not mean HMRC has approved the scheme, and reporting it does not mean the scheme fails. The page is a disclosure only: it does not change the tax in the computation.
Completing the CT600J in Tax Optimiser
Open the period’s Corp Tax Calculations workspace and choose Tax Avoidance in the Sections menu.
Step 1 — Add a row for each scheme
Click Add Tax Avoidance Scheme. Add one row for every Scheme Reference Number the company must report for the period. The form has room for ten schemes.
Step 2 — Enter the Scheme Reference Number
Type the number exactly as the promoter or HMRC gave it. It is always eight digits. A row whose number is not eight digits is highlighted, with a warning under the table.
Step 3 — Enter the date
The second column is the accounting period in which the expected advantage arises. Enter the date that accounting period ends. A new row starts with the end date of the period you are working on; change it if the advantage arises in a different accounting period.
Step 4 — Save and check the return
Click Save. As soon as there is a scheme with a reference number, Tax Optimiser:
- ticks box 65 (notice of disclosable avoidance schemes) and box 140 (CT600J enclosed) together, because HMRC rejects a return that has one without the other;
- adds a tax avoidance disclosure page to the computation;
- files each scheme with the return to HMRC;
- lists the completed form under Supplementary pages on the CT600 Document card, where you can view or download it.
If the period of account is longer than 12 months it is filed as two returns. The schemes you enter are reported on the CT600J of both returns.
CT600J box by box
Boxes J1 to J4 — Company information
The company name (J1), tax reference (J2) and the period covered by the page (J3 and J4). Tax Optimiser copies them from the return.
Boxes J5 to J50 — Scheme reference number
One box per scheme, numbered in fives: J5, J10, J15 and so on to J50. Each holds one eight-digit Scheme Reference Number, in the order you entered them.
Boxes J5A to J50A — Accounting period in which the expected advantage arises
The date beside each reference number: J5A goes with J5, J10A with J10, and so on. It is the date you entered for that scheme.
What Tax Optimiser checks, and what it does not do
Tax Optimiser checks that each Scheme Reference Number is eight digits. A row that is not is still shown on the CT600J so you can see it, but it is left out of the submission to HMRC until it is corrected. Correct or delete highlighted rows before you file.
Only the first ten schemes are filed, because that is all the form holds. If the company has more than ten to report, contact HMRC about the rest.
Tax Optimiser does not decide whether arrangements are notifiable, check a number against HMRC’s records, or adjust the tax computation for the scheme. Take the number from the promoter’s form AAG6 or HMRC’s letter.
Common questions
What is the CT600J?
The CT600J is the supplementary page of the Company Tax Return for disclosing tax avoidance schemes. It lists the Scheme Reference Number of each scheme and the accounting period in which the tax advantage is expected. Box 140 on the CT600 is ticked to show it is attached.
What is a Scheme Reference Number?
An eight-digit number HMRC issues when tax arrangements are disclosed under the Disclosure of Tax Avoidance Schemes (DOTAS) rules. The promoter gives it to each client who uses the scheme, usually on form AAG6.
Do I report the scheme every year?
Yes. Report the number on the return for each accounting period in which the company expects a tax advantage from the scheme, not only the first.
Which boxes on the CT600 does the CT600J affect?
Box 65, notice of disclosable avoidance schemes, and box 140, which shows the CT600J is enclosed. Tax Optimiser ticks both as soon as a scheme is entered. No tax figure changes.
How many schemes can I report on one CT600J?
Ten. The form has ten rows, J5 to J50.
Does reporting a scheme mean HMRC accepts it?
No. A Scheme Reference Number only shows the arrangements were disclosed. HMRC can still enquire into the return and challenge the scheme.
Where to go next
- Corporation Tax in Tax Optimiser — the full journey from trial balance to filed return.
- CT600 box-by-box guide — box 65 and the supplementary page boxes on the main return.
- HMRC’s CT600J guidance — the official notes for the page.