Accountant claims my SIPP contributions won't lower my basic-rate tax bill. Am I wrong?
I am a basic-rate taxpayer filing a Self-Assessment return for 2025/26. Because a portion of my income didn't qualify for a tax deduction, my accountant sent me an SA302 showing £1,299.40 in Income Tax due on £20,502 of gross income.
To offset this, I deposited £5,200 net (£6,500 gross) into my SIPP before April 5th.
When I asked my accountant to add this to my return to lower my bill, he replied:
"As your taxable income falls within the basic rate band, there is no further tax relief available to claim through your tax return. The provider already claims the basic 20% tax relief automatically."
I know I don’t get a cash *refund* directly from HMRC because the basic relief went into the pot. But shouldn't he still declare the SIPP contributions on my return to extend my basic-rate band / personal allowance, bringing my actual tax liability down to £0?
If he files without entering my SIPP data, won't HMRC assume I didn't make a pension contribution and stick me with the full £1,299.40 bill?
Am I misunderstanding how Self-Assessment handles basic-rate SIPP contributions, or is my accountant completely missing the point?
Thanks