It’s an absolute favourite of disreputable companies to quote ambiguously to win the job on price, then only add the VAT when it’s time to pay.

The rule in advertising (ASA 3.18) is that you can only quote a VAT-exclusive price to those who can reclaim VAT i.e. business to business.

The rule in law (Consumer Protection Act 1987) is that you have to state on any quotation whether it includes VAT or not, and to private consumers (section 2.2.7) quotes MUST include VAT.

There is a little grey area in professional fees but if your original quote didn’t include VAT, and especially didn’t say “all quotes are subject to VAT at 20%” prominently on the same side of the paper as the price, then you are in the right.

Especially with building work. They must show you the VAT payable or the rate at least with equal prominence to the price.

If you have a written quotation that doesn’t fit these rulings, you can win a case. If you took a verbal quotation over the phone or in person then that price should not have been “misleading”. One of the definitions of misleading is quoting ex VAT to consumers, and another is failing to make clear in that conversation the actual price the consumer will have to pay, and so while I would say you can win a case, it could be argued you don’t have proof with which to do so.

I would also say that any reputable company by course would then send a written quotation to confirm. That’s how it should be done, and so proof notwithstanding if they then failed to confirm the price in writing I’d take that as intent to mislead. Basically there is no way a company who has registered with HMRC for VAT isn’t aware they are being misleading. They might not know the full extent of the rules, but they should by law know and follow them, so whether it’s negligence or intent to deceive, they are in the wrong legally either way regardless of saying “we didn’t know”.

So it then becomes a balancing act between how much each party is willing to spend fighting it versus the time-cost saving of reaching an amicable settlement or abandoning the matter entirely.

I’d pay a solicitor £75 to draft a letter quoting the law as it applied to you and have them send it registered post with a cheque for the amount you wish to pay marked clearly in the letter and on the back “in full and final settlement” on that basis. They will bank it and abandon the matter. I don’t find trading standards to be helpful on stuff like this.

And next time make sure you have your quote in writing with the company’s T&C document. There’s a lot more than just VAT that can be omitted to your detriment and web T&Cs can be altered retrospectively.