A great deal has already been said about the junior doctor contracts row, so I will keep this short.
As the years have passed, working as a doctor in the NHS has become more and more about service provision and meeting targets than about good patient care. As training overhauls like MTAS, eportfolios and the degradation of the firm structure have come to pass, training itself has become more of a tick box exercise. You are no longer rewarded for actually being a great doctor, and can easily work your way up the system by simply looking good on paper. For doctors who care, and who chose the profession as a vocation, this is incredibly demoralising.
The current political storm has revealed the extent of this disillusionment: many doctors are already at the end of their tether. Little things like having night-time resting facilities, access to a locker, or being allowed to park on hospital grounds for late shifts, magnify the more fundamental issues of adequate break times, poor management and punishing rotas. Meanwhile, external opportunities for doctors are increasing, whether it be working abroad, in locum agencies or changing career altogether, the pull to leave the NHS is getting ever stronger.
In other words: if junior doctors had any doubts about staying in medicine, the imposition of the new contracts will be more than enough to erase them.