Misti the government has a mandate for a 7 day NHS. It was one of the reasons I voted Conservative (and I am sure I was not alone).
Sure. But they could fulfil their election promises in a number of different ways - for eg, by employing more doctors (as well as other paramedicals - a true 7 day NHS will require more of everyone, including technicians and administrators).
Mandating a 7 day NHS is all very well, but you can't have a 7 day NHS (or indeed any NHS) without doctors. Doctors, like all employees, retain the right to withhold their labour, either through legal strikes or by voting with their feet and going to work elsewhere, as many are doing. You might disagree with them, as is your right, but you can't stop them short of imposing slave labour as a condition of medical training.
Ultimately, you can't argue with economics: if you wish to employ a resource that is in short supply, then you have to be prepared to pay the going rate, or to offer other inducements. What this contract does is to reduce effective pay for a significant minority of doctors (often those working in the most demanding areas) and, in most cases, to worsen their already difficult working conditions. They would be stupid to agree to it, and I think the one thing that we can all agree on is that doctors are not, on the whole, stupid.