You can give away any amount of cash as gifts to whoever you like as there are no actual limits BUT there are ramifications involving limits in the following circumstances.
1. If you die within 7 years of the date of making any cash gifts , the value of your your estate includes gifts made during that period over the permitted annual gift allowances, and if inheritance tax is triggered, this will have to be paid.
2.
If you don't die but need to into care home and can't afford to pay the fees yourself, the local authority can look at previous disposals of assets or cash and treat the gifts as intentionally depriving yourself of capital, particularly if the gifts were made as a deliberate attempt to avoid paying for care home fees. There are no annual limits or thresholds for intentional deprivation, but if you were in good health at the time of the gift and a good few years have lapsed, such gifts are unlikely to be treated as intentionally depriving yourself of capital.
While not relevant to OP question, if you gift other forms of property away such as a house or a valuable painting for example, you may have to pay capital gains tax on the notional value of the hypothetical gain from the disposal during the relevant tax year.
Always take professional advice before taking any significant financial decisions.