The Ritz in Brighouse, an 80-year-old music venue in West Yorkshire, has been given until 28 February to change its name or face legal action from the Ritz London hotel.
The Ritz Brighouse is owned by Glenn Smith, who received an e-mail from lawyers which he dismissed as a scam until it was followed by a letter.
It instructed Smith to also remove all online references to the name, including the website which currently operates as www.liveattheritz.com.
The venue has operated as the Ritz since 1937.
Smith now fears that the business may close before the end of the week, unless he forks out for an expensive re-launch.
A statement on the website reads: "In light of recent unforeseen events in relation to commercial trade makes, trade names and Internet Domain Name infringements, the name ‘Ritz' will no longer be used as our trading name and will cease trading as ‘The Ritz' from 26 February 2017.
"We would wish all our loyal patrons to know that after taking the appropriate legal advice the owners of the Ritz Brighouse have absolutely zero alternative but to take this action. The legal position is clear in that there are other Third Party commercial entities that have the right to prevent us from using the name "Ritz" in any shape or form, and sadly this situation has only recently been brought to our attention.
"You will appreciate that this is a most regrettable and unfortunate situation after 80 years of trading the business under this name.
"We will of course keep you updated as to what the future holds for the former ‘Ritz' business. We can assure you that we are working very hard indeed and that we are determined to keep the building itself open and the business operation trading as per usual if at all possible after this blow which has simply come out of the blue.
"Many thanks for your continued support."
The Ritz London declined to comment.
It cost the company around £20,000 to change the name to Kettering Venues.
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