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 here Tax on savings interest
and 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
and Inheritance Tax: general enquiries
You may also want to review the guidance at How Inheritance Tax works: thresholds, rules and allowances