What does the declaration actually say?
The wording on the form is short: "I declare that the information given on this return is correct and complete to the best of my knowledge and belief."
Each piece matters. "Correct" means the figures are right as far as you know. "Complete" means you have not left anything out, like a source of income you knew about. And "to the best of my knowledge and belief" is the part nervous directors skip over: it measures you against what you honestly knew and believed when you signed, after taking proper care. It does not demand a level of perfection that even accountants cannot promise.
Who is allowed to make it?
HMRC's guide to the return says the declaration is made by a proper officer of the company, or by a person the company has authorised to make it on the company's behalf.
In everyday terms, for a small company, that usually means a director signs. A company can also authorise someone else, such as an accountant or agent who files for you, to make the declaration on its behalf.
One thing does not change either way. Whoever presses the button, the directors stay legally responsible for the company's records, accounts and performance. Signing is a job someone does; responsibility is not something you can hand over with it.
What are you actually promising?
You are promising honesty and care, not perfection. If you gathered the right records, answered the questions truthfully, and checked the figures as well as you reasonably could, you have done what the declaration asks.
Mistakes still matter, but how they matter depends on how they happened. There are penalties for incorrect returns, and when HMRC considers a penalty it looks at why the tax was wrong and whether you told them as soon as you could. An honest slip that you put right quickly is a very different conversation from a figure someone chose not to check, or chose to hide. If you spot an error after filing, you can amend the return, and our guide on fixing a filed return walks through it.
So the declaration is not a trap. It is HMRC asking one fair question: have you been honest and careful? If the answer is yes, sign it.
What if my accountant prepared the return?
You can get an accountant to prepare and file the return, or do it yourself. But hiring help does not move the responsibility. The government's own guidance for directors puts it plainly: you can hire other people to manage some things day-to-day, for example an accountant, "but you're still legally responsible for your company's records, accounts and performance".
That is why it is worth actually reading the return before it goes, whoever prepared it. The declaration is being made about your company, in your name or with your authority, and the responsibility for it sits with the directors either way.
How does the declaration work in SimpleReturns?
The same way, just with nothing hidden. Before anything is sent, you see every figure on screen with the reasoning next to it, so you can check each one against your own records. Only when you are happy do you make the declaration at the sign-off step, and nothing is transmitted to HMRC until you have. You are never asked to declare something you have not seen.