Amazon issued, and subsequently withdrew, a legal threat to a fishmonger over his use of the phrase "prime day" to advertise fish, despite claims it has been used by sellers for centuries.

Robin Moxon, who owns four shops and a fish smokery in London, received an email from lawyers acting on behalf of the online retail giant asking for references to "prime day" boat fish to be "pulled" from Moxon’s website to avoid shoppers mistaking it for an Amazon offer.

Following the request to remove the wording, the high street seller said he phoned solicitors at Morgan, Lewis & Bockius, and explained that the term had been used by fish sellers for "hundreds of years", a response that has since elicited an apology from both Amazon and the legal practice.

Amazon has registered "prime day" (which is its slogan for an annual two-day event of deals and offers for its Prime members) as a trademark.

But Mr Moxon said "prime day" catch was a "nice, neat little phrase" fishmongers used to advertise they had in stock top quality fish – such as turbot, brill and Dover sole – bought from trawlers that fish sustainably for no longer than a day at a time.

Despite the online retailer backing down, Wandsworth resident Mr Moxon called Amazon’s attempt to stifle the use of "prime day" branding "heavy handed", and said the phrase had been popular among fishmongers before billionaire boss Jeff Bezos "was a glint in his mother’s eye".

"This phrase has been used by many people probably for hundreds of years, and I’ve been using it regularly for 30 years.

"This phrase was being well used probably before Amazon existed in this country and before Jeff Bezos was a glint in his mother’s eye.

"I have used it and always will use it, and I don’t see how it can affect its business. It was heavy handed and offensive," Mr Moxon said. 

According to an email seen by PA, Amazon’s lawyers wrote to Moxon’s on June 21 – the start of its Prime Day sales – expressing "concern" that consumers were "very likely to think that a ‘Prime Day’ sale event/advertisement coinciding with Amazon’s Prime Day is offered in association with Amazon when it is not".

After a telephone conversation with Mr Moxon, the firm followed up with a second email later that day apologising "for any inconvenience" after "clarifying the root of the term ‘prime day boat’ in the context of the fishing industry".

A spokesman for Amazon said: "This email was sent in error and we apologise for any inconvenience caused."