Step father in law sending money to fiancé

So my father in law would like to gift my fiancé £45000 as a cash gift. Would he have to pay taxes on the £45000?

Hi,
There are no tax implications for transferring savings to a UK bank account unless they generate interest or dividends.
These would then potentially be subject to tax.
Further guidance can be found here:
Tax on savings interest
Tax on dividends
Thank you