He didn't write it very well, but it is a fair point he's trying to make.

I don't go to the opera so don't want to pay for it. Same with the wars in Iraq and Afghanistan - I don't think we should be there and don't want to pay for that either. If the government had to go to the country and say "We want £x off you to pay for a new opera house, or to fight an illegal war. How about it?" it could end up a fairer system and as for cashflow, money in money out over a period so sometimes one department budget may subsidise another for periods of time but so long as each department squares up as agreed there is no problem.