One of the fundamental aspects of the general tax rules and tax systems—this comes from Supreme Court decisions in IKEA and Canderel—is that tax rules ought to provide taxation on the truest picture of your income. To that end, the basic scheme of the act, currently, for a large majority of taxpayers, requires accrual accounting, which means that in any year, you pay tax on the amount that you earn in that year.
Back in the 1980s, as I said, there was a general shift in the tax rules, away from what we call billed-basis accounting, whereby you include something in income when you send out the bill, to this more comprehensive, truer picture of income, the accrual system. Exclusions were made back then for certain designated professionals. Of course, lawyers are on the list, but there were also doctors, chiropractors, I think maybe veterinarians, and others.
However, the reasons for excluding them from the general rule that provides the truest picture of income no longer exist right now. Therefore, as part of the tax expenditure review, it was determined to be inappropriate to provide for continued access to this tax deferral, rather than applying the general rules that apply to other taxpayers. This could include other professionals, such as engineering firms and the like, It's instead of having two sets of rules, with a favoured category and then the general one.