Given David Cameron's constituency includes Charlbury and West Oxfordshire, I suspect I know which of those two options it will be...
Is there any evidence this change results from an intervention by Cameron?
However, even if that were the case, one of the biggest criticisms of Cameron is that he is 'out of touch' with ordinary people because his parents chose to send him to a good school, he was a member of an eccentric drinking club at Oxford and has appointed several old Etonians to senior positions in Government.
If Cameron's constituents are writing to him to complain about routine over-crowding in Standard, it is perfectly proper for him to make representations to the DfT on their behalf, as any MP can do.
If Cameron had replied to his constituents along the lines some here would have liked, ie:
'There is no problem. You just need to move down the train. We have to ensure people from Worcester travelling on First Class Advances for £50 don't have to share a bay of seats with strangers'
...then he would have stood accused of being an 'out of touch' toff, again.
Bear in mind that if Cameron uses the train to get to Oxfordshire, it will be First Class, so the self-interested decision of he and his toff friends would have been to do nothing and stick with 2.5 coaches of sparsely populated First. Yet the decision has gone the other way.
I'm not a great fan of Cameron, and I go along with the 'wicked Tories' criticisms in some areas of policy, but 'wicked Tories made me pay more for First Class/made me share a '4' with strangers' is verging on the surreal.
Two final points:
1. If we're going to try and politicise this, are any of the other parties in favour of keeping the status quo?
2. You get a distorted view amongst rail enthusiasts, because it's our hobby and we (me included) like the occasional First Class treat, with lashings of complimentaries in a coach as quiet as possible. The reality is that most 'ordinary' folk, particularly family groups, struggle to afford Standard fares and could not dream of going First Class. It is right that these people are the focus of attention at the DfT.