£350 million per week equals over £18 billion a year. That’s is a massive spending commitment for the NHS and is far more than will actually be saved by Britain leaving the EU.
So to find over £18 billion extra for the NHS budget means not only leaving the EU, but also not replacing any of the EU’s current grants with UK government money (e.g. nothing to Cornwall). And then you still have to find another £5 billion. All on top of public spending figures which already are very squeezed.
So a Tory party led by Boris Johnson would be dodged all the way through a general election campaign by a spending commitment to the NHS that it would find impossible to meet. Unless it is willing to add in massive tax rises. Either way, it’ll be politically devastating.
Boris Johnson campaigned in the referendum on an NHS spending promise he’s never going to be able to keep. Which is quite a problem for the Tories if he’s their leader.