Tell HM Revenue and Customs (HMRC) as soon as possible if you’ve made money you need to pay tax on and haven’t told them about it.
This could have happened because you:
- didn’t realise you needed to tell HMRC about it
- weren’t sure how to declare it
- didn’t declare it because you couldn’t pay the tax
If you contact HMRC first, they may consider your case more favourably.
You don’t need to tell HMRC about income you’ve already paid tax on, eg wages. But if you don’t think enough tax has been taken on your employment or workplace pension, you should tell HMRC.
- renting out property
- capital gains, eg from selling property, valuable items or shares
- working for yourself, including if you buy or sell items regularly, eg at car boot sales or on the internet (you’ll also need to register as self-employed)
If this income takes you over your Personal Allowance, you’ll pay tax on it.
Declare the income on a tax return
If you’re already registered for Self Assessment but haven’t declared all your income, you can make a change to your return.
If you don’t usually send a tax return, you can register for Self Assessment to declare any income you haven’t paid tax on from the last 4 years. You’ll need to fill in a separate tax return for each year.
You’ll get a letter telling you what to do next after you’ve registered.
You must register for:
- Corporation Tax if you run a limited company
- VAT if your taxable annual business turnover is more than £81,000
- PAYE for employers if you employ people
If you don’t report this, you may have to pay both:
- the undeclared tax
- a penalty worth up to double the tax you owe
You can be prosecuted if you give false information about the tax you owe. If you tell HMRC as soon as you can, they may consider your case more favourably.
You may be eligible to tell HMRC about undeclared income through an ‘offshore disclosure facility’ if:
- you haven’t told them about your foreign income
- you’re not paying the right amount of tax
- you’ve previously made an incorrect claim
- you’re behind with your tax
If you’re not eligible to use an offshore disclosure facility, but still have tax to declare, contact HMRC’s Offshore Co-ordination Unit.