A client told me he was outside Making Tax Digital because his profit was under £50,000. He had checked with a chatbot first, and it agreed with him. His turnover was well over the line, which is the number that counts, and he should have started in April.
That is the shape of almost every AI tax correction I make. The model is rarely inventing from nothing. It is confidently repeating a rule that was true two years ago, on exactly the question where being out of date costs money.
TL;DR: AI tools get UK and UAE tax wrong in a predictable way. They fail on rules that changed in the last eighteen months, and they fail confidently. These are the five I correct most often, with the actual rule and a primary source for each. Check the source, not the summary.
Why does AI get recently changed tax rules wrong?
Two things stack up. Training data has a cutoff, so a rule that changed in April 2025 or April 2026 is thinly represented next to a decade of content describing the old position. The open web reinforces it, because accountancy blogs from 2019 still rank and still say the old thing.
You get a model answering in a hedged, statistically likely way rather than an accurate one. A 2026 NerdWallet study of consumer AI tax answers found chatbots quoting a standard deduction that was out by nearly $3,000, and claiming an electric vehicle credit that had already been repealed (NerdWallet, 2026). I wrote about the UK version in May, when HMRC blamed AI summaries for a spike in late VAT returns.
Which five rules do I keep correcting?
The MTD threshold is turnover, not profit
Qualifying income for Making Tax Digital for Income Tax is total income from self-employment and property before expenses (GOV.UK). Anyone over £50,000 for 2024-25 joined from 6 April 2026, with £30,000 following in 2027 and £20,000 in 2028. HMRC expects around 780,000 people in that first wave (GOV.UK). Ask about "the £50,000 threshold" without saying turnover and you will often get profit back. More on the first quarterly deadline.
UAE corporate tax is not 9% on everything
The 9% rate applies to taxable income above AED 375,000. Below that the rate is 0%. I have had business owners budget 9% of total profit from the first dirham, which badly overstates the bill on a small trading company.
A UAE 0% rate is not an exemption from filing
This one costs real money. Registration is mandatory whatever your rate, and the return is due within nine months of the period end (Federal Tax Authority). Late registration carries an AED 10,000 penalty (Ministry of Finance). Free zone clients are the most exposed, because "0%" gets heard as "nothing to do". The substance rules are a separate trap I covered here.
A £12,570 director salary is not tax-free
It is free of income tax and employee National Insurance. It is not free of employer National Insurance. The secondary threshold dropped to £5,000 from April 2025 and the rate is now 15% (GOV.UK), so a £12,570 salary generates £1,135.50 of employer NIC. The £10,500 Employment Allowance would cover that, except a company whose only employee above the secondary threshold is its sole director cannot claim it (HMRC NIM06545). More on the salary and dividend maths.
Furnished holiday lets lost their special treatment
The FHL regime was abolished from 6 April 2025 (GOV.UK). Finance costs now get basic rate relief at 20% like any other let, capital allowances on new spending for furnishings are gone, and the letting is no longer a trade for capital gains reliefs. Ask an AI about "holiday let tax advantages" and it will describe a regime that no longer exists. What replaced it.
How should you actually use AI on a tax question?
Use it as a starting point, never as the answer. I use it every working day, but if the output contains a number, a date or a threshold, I open the primary source first.
The tell is confidence about a recently changed rule. When a model gives a precise figure without naming the tax year it belongs to, check it.
Frequently Asked Questions
Can I trust ChatGPT or Claude for UK and UAE tax answers?
For understanding a concept, they are useful. For a rate, threshold or deadline you will act on, no. Treat every number as unverified until you have seen it on GOV.UK or the FTA site.
What do AI chatbots get wrong most often about UK tax?
Rules that changed in the last two years. The MTD qualifying income test, the employer NIC secondary threshold cut to £5,000, and the abolition of the furnished holiday lettings regime are the three I correct most.
Why does AI get the UAE free zone and corporate tax rules wrong?
The regime is young and still being clarified, so there is little settled content to learn from. It collapses "0% on qualifying income" into "no tax and no filing", which is wrong and expensive.
If a chatbot has handed you a number you are about to file on, send it over and I will check it against the primary source. Happy to run through your MTD position or a UAE filing obligation with you.