Oh my god, a $100k salary would be taxes at 42%, plus a 25% VAT on general spending, that's just insane...
For each 2£ you earn above 100K, your income tax allowance is reduced by 1£. At 125K, your allowance reaches 0. The result is that between 100K and 125K your marginal tax rate is 60%. At 125K it goes back to 40%.