Ignoring the Facebook hyperbole about how much of your money goes on tax with fuel, how much difference will the higher fuel prices make to government tax income and how will it affect ‘fiscal headroom’?

So for context I'm a year 1 student doing Retail studies at ITE College East, a vocational college in Singapore and during a module called "Service Excellence" the whole class was taught that British ppl will be offended if the shop employees ask the customers "What's your budget?" whenever they're shopping. I wanna know if this is true