… is that the prime minister can take the train.
The tabloids are trying to turn this into a scandal, because the PM’s conspicuous red box of official papers seemed to be unguarded. Maybe it was and maybe it wasn’t. I won’t suggest that riding in the first-class carriage is exactly a recipe for inculcating modesty, but look at this photo

of David Cameron working while he travels. He looks more like a public servant than Barack Obama ever could, despite the fact that he is doing fundamentally the same job. And if the cost of that is that some important papers may be left temptingly out on the table occasionally, I think it’s well worth it.
Part of the cost may be maintaining a monarch, as well. I like to mock the notion of monarchy (as here and here) as inimical to democracy. I still think the idea of assigning important roles in society by heredity both ridiculous and pernicious. But there is a strong pragmatic argument on the other side that a constitutionally neutered monarchy keeps the atavistic and campy royal circuses away from the levers of power.
I’d say, far from being a scandal, this photo is one that Downing Street and the British people generally ought to be proud of. Even if he does seem to get a whole table and block of four seats to himself.