Is it legal?

A certain bookmaker is taxing me 6 percent of my winnings on all tote bets .
Just need clarity if this is legal or not ?
Thanks 

why bet with them?

Must be the Open Bet?

Tote bets 
Any tote bets,  swinger , trifecta,  quartet , pick3 , pa, jpt,  p6

You must be taking the open bet to get taxed

Most the big racing bookies offer both the open bet and Tote bets

Your choice which one you use, most the pro players use the open bet and pay tax so there must still be benefits to them

And if you are paying tax on the open bet so are the bookies

....doubt it as one of the largest here takes no tax on all their tote exotics.....and from time to time add in your stake on open win and place bets.....oops

there are many bookies that don't tax winnings on the open bet

there are also many bookies that offer shit odds on all events as opposed to those that offer better odds, eg they bet 17/20  as opposed to 9/10 on rugby h'cap lne 
most also screw you on double chance odds - today 4.1 the draw and 3.7 liverpool should be 1.94 and they offer 1.81  - a difference of 3.7%, but the vast majority of punters simply take the bad odds - your money your choice, but if you want your money to last longer make a effort to understand