How can it be a stealth tax when it's governed by independant organisation to keep the Lottery in check with all the rules and regulations.
It's to do with what the government used to pay for out of taxes and duties, and now don't pay for because the lottery commission exists and does it. The amount of money museums, charitable foundations and so on receive compared to pre-national lottery days will vary depending on who you ask (Conservatives under whom it was set up and the lottery commission will say more of course but then they would do!)
But what is clear is that it is the less-rich people who buy the most lottery tickets. If you worked it out in terms of what people pay in income and council tax versus what they spend on the lottery it would look even worse. Considering they don't pay much in the way of council tax or income tax, via the lottery the low waged or unemployed people in this country still contribute a disproportionately high amount of money to what the government used to fund itself out of everyone's money and now no longer does.
You can bet your life that people will always buy lottery tickets in the hope of a sudden boost out of poverty, and that if there were 2 sorts of lottery tickets where the one which had no contribution to the lottery commission (but equal chance of winning) was half price, people would just buy twice as many cheap ones.
So yeah, stealth tax. Grumble over.