An application by Specsavers to trademark the terms "should've" and "shouldve" to protect its advertising catchphrase has been approved.
The high street optician's application to safeguard its slogan "Should've gone to Specsavers" has been deemed valid by the Intellectual Property Office (IPO) and third parties now have two months to raise any objections.
The catchphrase is central to Specsavers' marketing campaigns, with adverts featuring hapless people who could have avoided embarrassing situations had they visited the optician beforehand.
Trademarking a single word is unusual but has been done by companies in the past.
Carlsberg successfully registered the word "probably" in the UK after establishing the slogan "Probably the best lager in the world".
McDonald's has trademarked the phrase "I'm lovin' it" and Nestle has done the same with "Have a break" for its KitKat bars.
The IPO said applications for trademarks on common words could be made where they were linked to a company through use or association.
An IPO spokesman said: "We can confirm that the application for the trademark in question was published on August 12.
"Objections to the trademark application can be raised for a period of up to two months from the publication date."
Tania Clark, partner and trademark attorney at intellectual property firm Withers & Rogers, said: "It is surprising that the Office has accepted this trademark for a single word, which is a verb in common usage.
"While such registrations are not impossible to obtain - as this decision demonstrates - it means that the retailer could soon have the right to exclude others from using the word 'should've' or 'shouldve' when communicating about certain classes of goods, including optician services, medical hearing aids and eyewear.
"This monopoly right could make life extremely difficult for rivals who may want to use the word in their own marketing messages in future. In light of this, we would expect more brand owners to try to obtain a registration for a single word used in their advertising or marketing campaigns in the future. After all, the ability to exclusively own the right to use a commonly-used word in your communications activity is an incredibly powerful brand marketing tool."