QUOTE(porilo @ Jun 17 2012, 12:31 PM)
I have an Oyster card but I don't claim anything for travelling because when I have to travel to visit students at home I have already incorporated the cost of travelling in the lesson charge, so it would not really be honest to make a separate claim for travel expenses.
One doesn't necessarily have to do with the other - by doing it that way, you are actually putting up your taxable income.
If you are charging more for travelling to students' places (which of course you should, and it imho shouldn't just be the travel expense, but also cover the travel time), all the MORE reason to claim the travel expense.
Simple example: You charge ?30 for a lesson, but ?40 for travelling to the student. Your ticket/mileage costs ?2 each way. If you don't claim, you make ?40 taxable profit. If you do, only ?36 (note: That's not "earning ?6 extra", because it probably doesn't even cover the extra time). The latter is the more clever thing to do for tax purposes.
Whether someone travels so much that it is worth the hassle in general is of course a different question.