As reported earlier this year, HMRC's Property Tax Campaign declaration deadline is next Friday (9th August).
People who have sold non-primary residences, or second homes, and have not declared any gains can voluntarily declare their liability directly to HMRC by next Friday. They then have up to September 6th to make a full payment to clear the tax.
If the deadline is missed, HMRC will be following up on the list of property sales they have, which they deem have not been declared. Anyone contacted and found to have not declared their liabilities would face penalties and possible criminal prosecution.
People who get in touch before August 9th have been promised lower penalties and no further action.