HM Revenue and Customs (HMRC) has issued a stark warning to businesses against relying on artificial intelligence (AI) summaries for VAT deadline information, cautioning that incorrect advice could result in penalties. The tax authority highlighted that some AI platforms incorrectly claim that VAT deadlines falling on weekends can be paid on the next working day, which is not the case.
HMRC Issues Warning on Social Media
In a post on X (formerly Twitter) on June 18, 2026, HMRC shared a graphic titled 'Misleading information' stating: 'Some AI platforms claim weekend VAT deadlines can be paid on the next working day. This is incorrect.' The post further clarified: 'The VAT deadlines remain one month and seven days after your VAT period.'
The accompanying text warned: 'Not all online advice is accurate. Submitting your VAT return late can lead to penalties, and late payments can accrue additional interest. Always check official guidance rather than relying on AI summaries.'
Consequences of Late VAT Returns
According to HMRC, submitting a VAT Return late can lead to penalties, and late payments may accrue additional interest. For each late VAT Return, a penalty point is issued. Once the penalty point threshold is reached—determined by the business's accounting period—a £200 penalty is applied, with a further £200 penalty for each subsequent late submission while at the threshold.
The amount charged for late payments depends on how late the payment is made. Penalties increase after 16 days and again after 31 days.
Official VAT Deadlines and Requirements
A VAT Return is a form that businesses complete to inform HMRC of the VAT they have charged and paid to other businesses. Typically, returns must be submitted every three months, known as the 'accounting period.'
Official guidance on Gov.UK states: 'If you're registered for VAT, you must submit a VAT Return even if you have no VAT to pay or reclaim. The deadline for submitting your return online is usually one calendar month and 7 days after the end of an accounting period. This is also the deadline for paying HMRC. You need to allow time for the payment to reach HMRC's account. You must submit your return and make sure your payment reaches HMRC on or before the deadline, even if it's on a weekend or bank holiday.'
If the deadline is missed, HMRC will send a 'VAT notice of assessment of tax,' detailing the amount they believe is owed. A surcharge or penalty may also be applied for late submission or payment.
Businesses Urged to Verify Information
HMRC emphasized the importance of verifying tax information from official sources rather than relying on AI-generated summaries, which may provide inaccurate or misleading advice. The warning comes amid growing use of AI tools for quick answers, but HMRC stresses that such tools are not a substitute for official guidance.
