US & UK taxpayers must be careful when planning to make any charitable donations to ensure that it is tax efficient.
A UK resident taxpayer should typically donate to a UK charity instead of a US charity due to the higher tax relief which can be claimed on the donation. Taxpayers who have both a US and UK tax liability should consider donating to a dual qualified US/UK charity to obtain the maximum relief.
If the charity of your choice does not have a dual qualified entity, then you should consider donating to a dual qualified Donor-Advised Fund.
Donations to these entities are recognised for tax purposes in both jurisdictions.