This doesn't appear to be tax efficient.<p>They donate 10% of your bill <i>after VAT</i>, so 8.3%. I'd actually be paying VAT on my donation. Meanwhile the charity can't claim back my income tax on the donation.<p>e.g. if my phone bill is £24/month, then £4 of that goes to the government as VAT, and TPO passes £2 of the remaining £20 to a charity of my choice.<p>Alternatively, if we don't tie the charity to the phone service, then I get charged £21.60/month for phone service (£18 + £3.60 VAT). And I can separately give £2/month to a charity, on which they can claim back 50p/month income tax (assuming 20% rate), so they actually get £2.50/month. (Unless they can claim back national insurance as well?) So I would pay less, the charity would get more, and the phone operator would do just as well... but would have to rely solely on the "25% of profits to charity" shtick in their marketing.