arose

Hi I currently have a couple of savings accounts with various banks but don’t earn more than 10k in savings annually. I fall within the 1275L bracket. However, my father has recently received his pension and would like to transfer 10k to myself and my sibling in order to contribute to a future house. I’m aware that tax doesn’t have to be declared on less than 10k in savings, but what about a 10k lump sum received once only in the current calendar year? Will I be liable to tax on this, and do I have to declare this or will my building society inform HMRC?