To Claim Or Not To Claim?

I am concerned about expenses.

The normal way, obviously, like everyone else. (People who run our country and whose wages we already pay also think it is OK to claim for moat-cleaning?) But also because, being self-employed, I am allowed to claim my business expenses against tax, ie I do not have to pay tax on income which goes on my expenses, so effectively you the British taxpayer cover 22% of my expenses - the rest I pay for myself. (Is that right? or is it just that the Treasury has 22% of my expenses less to play with? I was never good at maths.)

But it is not immediately clear what counts as a legitimate business expense. Paper obviously, and pens, writer-y stuff like that. Library membership, maybe? Internet access? The electricity I use to run the computer that I write on and the gas to heat the room that I sit in? Stuff your employer would usually pay for, basically. Stuff I can't do my job without.

How about this: after some moderate but bulky shopping in NYC (new winter coat: J'accuse) I suffered the indignity of having my suitcase burst apart at the seams on the flight home, turning up forlorn on the luggage carousel wrapped in accusatory bright orange Virgin Atlantic parcel tape. (Me: "That's my case! - Oh, no it isn't - Oh god, it really is.") So today I went out to buy a new suitcase, because I need it to go to the Hay Literary Festival at the end of the month (I am not reading there, but I am seeing other writers read, and using the opportunity to do some schmoozing of publishers, journos, etc - business trip? Fun weekend jaunt? Who can say?), to Milan in June (book tour, 100% business) and to France in the summer (holiday, 100% fun.) I didn't buy the most expensive case, nor did I buy the cheapest. (In fact I bought the lightest, because of budget airline weight restrictions and so I can lift it in and out of the loft by myself. Also, it is a bit bigger than my old suitcase, but not so much bigger that I will lose my mind. That's the idea, anyway.)

My point is: is a suitcase a business expense? I can't do my job without it; on the other hand, if I never went on another work trip again, I would still need a suitcase, plus I think that people who go on lots of business trips in normal jobs are not provided with luggage by their bosses (correct me if I am wrong.) Before the whole MP expenses scandal I would probably have claimed it without another thought: at least 22% of my travel is work-related. But now I feel sleazy and tainted by association. I feel like Hazel Blears. I do not want to feel like Hazel Blears. God prevent me from feeling like Hazel Blears. The value of not feeling like Hazel Blears is surely at least one quarter of a suitcase. (Hazel Blears: the kind of vomit you get from eating too much Nutella?)

Anyway, I don't know. Is it legitimate? Is it illegitimate? This is as confusing as Prince Harry. And multiply that by everything I buy which I sort of use for work but also use for other things - filing cabinet? *Assembly* of filing cabinet? I can sense it's going to be a very soul-searching, guilt-inducing tax return this year.

And don't even get me started on the leaky pipe underneath my tennis court. Totally interfering with my concentration on my second novel.