If you apply for a patent, you might think that you don’t need to do anything more, until the patent is granted, to gain patent box relief.
However, that would be a costly mistake.
If you have a patent pending, that you’re planning to use in a Patent Box application once granted, you must notify HMRC formally each year, so that they know that you will be apply for tax relief after your patent is granted. There is no special form for this, but it has to be done sometime in the relevant financial year.
Be sure not to forget this small, relatively unpublicised step, or you could lose out on years of tax relief.