Popular live music venue The Tramshed could be under threat if controversial plans to build flats next door go ahead, council bosses have been warned.
The Cardiff venue has proved a massive success since opening four years ago.
As well as being used by established acts like UB40 and Enter Shikari, it has also hosted gigs for several up-and-coming touring acts.
But its owners say plans for a new flat development towering over the site could cause massive problems to the booming business.
Daniel Ickowitz-Seidler, who runs the venue with business partner Richard Buck, has written a direct and strongly-worded letter to the head of Cardiff's planning department.
"The Tramshed music venue is at direct risk by this planning application," he said.
"Should planning permission be granted, it will unfortunately make the Tramshed unviable and unable to operate and could potentially cause the venue to close."
Until 2015, The Tramshed was a derelict shell of a building, a stone's throw from the city centre.
But a century-old Grade II-listed building, in Grangetown , was given a new lease of life as a gig venue.
Since it opened, it has become a hugely successful and popular gig venue, office space and yoga studio which has breathed new life into a formerly rundown building.
Its owners said they have since invested more than £1m in the business to make it "one of Cardiff's premier live music venues" and brought events to the city that would otherwise not have happened and that impact "should be recognised".
Mr Ickowitz-Seidler added: "Every year around 200,000 people attend Tramshed and we attract tourism to Cardiff, benefiting many hotels, restaurants and other businesses in the area.
"Furthermore we employ around 100 people a week at our events".
The plans are for a four to seven storey building including offices, apartments and flats immediately next to the Tramshed.
In their application, the developer says that the rear yard - where the new flats would be built - has "begun to deteriorate through lack of maintenance and repair".
But the Tramshed argues that it pays an annual charge to the building management company to ensure the area is well maintained.
The building management they pay is partly owned by the proposal's developer - who is also their landlord.
The yard is used by bands and acts to park tour buses. If the yard can't be used, spaces in front of the venue would need to be "limiting parking in the area further".
Cardiff's Tramshed has flats inside and they are gorgeous
Using the rear of the premises for taxis on nights that the venue has a late licence was a condition agreed with the council as to control the noise impact on local residents.
The security of artists could also be jeopardised.
Demolition work has started on the Track 2000 building in Grangetown, Cardiff
If it were given permission, the actual works could impact day trade of the cafe which is "crucial" to the business, say the venue's bosses.
Mr Ickowitz-Seidler concludes: "The development is a significant danger to The Tramshed live music venue and subsequently we strongly oppose it.
"Unfortunately it poses a great risk to the jobs of those employed by Tramshed and at our events.
"It could have wider negative effects on the other businesses in Cardiff, as well as a detrimental effect on the city's culture and music scene, if the venue closes".
The criticism from residents includes that it will create "abysmal congestion" at an area already congested by local resident, and people parking to use the city centre.
One said: "There simply isn't enough spaces for all the increased people that will be visiting/living in the proposed building".
The changing face of Grangetown and how it became Cardiff's most up-and-coming suburb
It is also described as "overbearing" and "out of character". One resident describes it as "plain ugly".
The deadline for objections against the scheme has now closed but a petition of names against them has been submitted to the planning committee.
It is the latest scheme to cause concerns from residents.
The developer, DS Holdings, has previously said this new development would create jobs and that the suggestion of flats is reaction from "Welsh Government and what Cardiff council want".
"It's going to be fantastic," he said.
The demolition of the Demolition work has started on the Track 2000 building in Grangetown, Cardiff is another which people fear will cause congestion and traffic problems.
Residents say they are not opposed to that derelict building being demolished and replaced, but its size means a potential for up to 170 cars which will further impact traffic problems.
