Cost to tax payer of Royal Family £38.2 million per year - about 62p per capita.

Estimated added tourist value £500 million. This is likely to be exaggerated (figures from the tourist board), but even if it is exaggerated ten-fold, that means a net gain to the economy.

I would still abolish the monarchy because I don't believe in hereditary superiority. I think that this is more important argument than the economic ones.