This is interesting.
Surely your business is all about profit and loss. After all, in accounting you have a profit and loss account. Technically, a bad debt is a loss and can be claimed as such, along with fair expenses incurred whilst trying to recover that debt. For a one man business, its probably easier not to account for it to begin with and just walk away, but what happens if you have an employee who you have paid to do the clean? If the amount owed is £50.00 and you have paid your staff £20.00 to do the clean your loss is still £50.00. If you contracted an outside debt collecting agency to collect on your behalf, they would recover the debt + expenses, so you would not be in debt any longer. If they failed to collect the debt and charged you £25.00 expenses then your loss is £75.00 - that comes of your bottom line on your profit and loss account. The £50.00 would be included in your turnover for the day, but the none payment entry may come several months later as a debit (being written off). But you would need to put a note into you paper work for that tax year detailing the loss (date work done, expenses incurred and date the debt was written off) incase of a Receiver investigation.
You are not claiming it against tax. The tax man is not giving you anything towards your bad debt. If you were paying tax on an annual turnover of £1000.00, you would only now claim turnover of £925.00 and would pay tax on the new figure, but you are still out of pocket by £75.00. The end result is the same as Matt's for not bothering with it in the first place, but the Receiver loves a paper trail, especially if there are other incurred expenses you are claiming that are directly linked with this case.
Ditto Ian.
Bruce