If so, what's the most you've lent someone?

I don't think I'd feel happy lending someone more than about £20 - even if they were in difficulty. Mainly because (a) I'd actually want back anything over that amount and (b) I'd feel bad for haranguing them for payment. I think I'd rather just give the money than lend it.

I did offer to lend a relative of mine several thousand pounds though for help with a deposit on their first house - I'm quite glad that they didn't take me up on the offer.