Isn't this the same argument of paying MPs less than they currently earn? We despise them so they should earn less and pay for themselves? The counter is that only the already wealthy ones can afford to be a MP and you get predominantly land owning Tories and Barrister Labour types applying.

If you're doing public service (such as being an MP or PM) I don't think you should pay for travel whilst doing your job. That's not to say that costs shouldn't be kept to a minimum and people shouldn't pull the piss - it's public money after all. But it's a far cry from forcing them to pay for their transport.