Christian charity is not a matter of a personal feel-good factor but of using the talents - literally and metaphorically - that we are given wisely.
Lest I appear utterly heartless at this festive season, perhaps I should point out that the women who beg on the Tube are also putting themselves, and the small children they usually have with them, at risk. The money they collect is not necessarily for their own benefit, and they may sometimes be acting under duress. How do I know this? Because I have tried to find out what I can about them and to think the matter through carefully.
There are probably better ways of helping them than encouraging them in such an activity.