Not a Brit, but my country (Australia) uses polymer for all notes, so I'm assuming they contain tallow too.

Technically, currency is the property of the reserve bank. It doesn't belong to us, so it is not our responsibility. It's like sitting on someone else's leather couch. Speaking of leather, 99% of all notes are contaminated with it because that's what most wallets are made of.

Cash isn't something I deal with much anyway. Why use cash when you can tap your Visa debit card against the EFT terminal? Vending machines accept credit cards, parking meters accept them, taxis accept them, every capital city has an "Oyster card" equivalent that can be recharged online via credit card. You need a credit card to buy snacks and drinks on most flights here. We've got one of the best 4G networks in the world to handle all these in-the-field transactions (planes don't use it though; they store the transaction token until landing instead).

Bills can be paid online without fees. Direct deposits to other people's accounts is a standard feature of online banking (no fees there either). Basic savings accounts with Visa debit access (payWave capable of course) are free.

We're a backwater, but we've got cash-free transactions almost completely covered. Privacy is the only real issue, but I'm not that interesting. I don't know why Britons are having such a hard time avoiding cash. Europe is usually ahead of the curve with these sorts of things.