Talks aimed at resolving a dispute over a new contract for junior doctors are entering their final agreed day.
Leaders from the British Medical Association (BMA) and the Government have been meeting all week to try to break the deadlock and prevent a fresh round of strikes.
There are hopes on both sides that a final agreement can be reached that deals with the crucial issue of Saturday pay.
It is possible that talks could extend beyond tonight if both sides feel progress is being made.
The BMA has said any deal would need to be put before junior doctors in a ballot, though that is expected to take several weeks.
The issue is sure to be debated at this weekend's junior doctors' committee conference, held by the BMA in central London.
Junior doctors stopped providing emergency care for the first time in NHS history during their most recent walkout.
More than 125,000 appointments and operations were cancelled and will need to be rearranged, on top of almost 25,000 procedures cancelled during previous action.