If you have employed a midwife to be involved in your birth, she has a duty of care to at least keep an eye on the proceedings, and to sit in another room while you did your own thing is really putting her registration on the line, because if anything bad was to happen to you or baby, she would be (at least partly) professionally liable, at least in the eyes of the NMC.
However, if she were to sit quietly in the room, I suppose that would be a different matter, although as people have said, it defeats the whole object.
As many have said, the chance of anything going wrong is really quite small, and it is just a question of how much risk you are prepared to take, much the same as having a VBAC or an amnio etc.
I had a friend who had a freebirth (she was a student m/w at the time), and she thought it was a fantastic experience, and would do the same if she had another baby.
If you do decide to go for it, I would suggest getting a plastic clamp or some sterilised string for the babys end of the cord, as it can still ooze when cut (and for several hours after).
Good luck in whatever you decide.
lulumama -
'it is a shame that we do not have traditional MWs, women who have not neccesarily trained medically but have attended lots of births and are trained in the traditions of birth...'
In Australia, where homebirths are getting increasingly difficult to source due to the archaic attitudes of the Australian equivalent of the NMC in certain states, noteably Qld, where they persecute and hound out homebirth m/ws, there are a lot of 'lay' m/ws around, who are untrained but have assisted with and, I suppose doula'd (dont know if thats even a word) and because they cant be struck off etc, they do a lot of the homebirths that trained midwives used to do.
sophable - I like the thought of being subversive!