Do I have to declare gifted money within UK and does it incur tax for the receiver?

Hello, I would like to transfer £24k to a friend (my ex partner) who helped my out financially over the years many times. It’s basically money that I owe her. I read online that Hmrc only allows 3k to be gifted tax free per year. This confused and surprised me. My question is- can I simply transfer this money to her without a. Having to declare it to Hmrc or b. Her having to declare it (aside from any interest it might earn) Thanks in advance

Hi Tim Cindersy,
There are no income tax implications on the receipt of a cash gift unless the cash gift generates interest or dividends.
These would then potentially be subject to tax.
Further guidance can be found her:
Tax on savings interest
Tax on dividends
There are no tax implications on the giving or receipt of cash gifts, but you may wish to speak to inheritance tax regarding any inheritance tax implications:
How Inheritance Tax works: thresholds, rules and allowances
You may also want to review the guidance here: 
Inheritance Tax
Thank you.