It's not only the case that it is done for a fee either. I know of a couple expecting a baby through a surrogate who is a close family friend and who considers it an act of love to help them have the baby they desperately want.
I think that the UK probably has struck the right balance in removing the potential for financial coercion, even if the current status quo isn't perfect. The psychological wellbeing of the surrogate obviously has to be taken into account also, and I am far more comfortable with the situation where the surrogate knows the family and will know the baby, rather than one in which a stranger is a "womb for hire".