When I last filled my Self Assessment form in I was asked about what expenses I had claimed with my regular employer.
To me, a claimed expense can either be
a) a business expense where I pay for something for the benefit of the business with my own money and claim it back. For example, I may buy stationery, hire a car, get a flight. These are all expenses I need to claim to do my job.
b) a personal expense which is of benefit to me that my employer pays for and is a perk of the job but isn't essential in order for me to do my job. For example, the company may allow me to entertain clients, stay in good hotels, eat at the best restaurants and will reimburse me.
The company could insist that I bring a packed lunch, have only work- related meetings with clients, stay at the cheap hotels but don't. I consider this to be a bonus on top of my salary.
But the SA form doesn't distinguish between the two. I could understand that if I buy something for myself and the company pays for it that this should go towards calculating my annual salary and therefore which tax bracket I fit into.
But if an expense is simply an actual business expense, why should this potentially affect how much tax I pay?