"It's not just Sale. Leicester rely on 20,000 people [coming to games] to keep them going. Bath rely on 14,000 spectators week-in, week-out. It's the whole professional game as we know it.
"And at the very top, the RFU are in the same boat – as is all other sport. It looks like only Premier League football is OK."
According to a report by Oakwell Sports Advisory, Premiership clubs stand to lose a combined total of approximately £67.2 million (NZ$130.6m) of match-related revenue if no supporters are allowed into games for the 2020-21 season.
That figure comprises tickets, food and beverages sales and corporate hospitality and also factors in a 15 percent dent in broadcast and commercial income.
With the Rugby Football Union and Premiership Rugby hoping for a rescue package from the Government, Diamond underlined the "dire situation".
"We're not a standalone industry," he added. "Every industry is going through it, but our business relies on people coming through the gates.
"Central funding has been cut enormously because the RFU is making no money and you can't live off your TV money. The TV money that comes in is far less than what the salary cap is.
"We're all in a very poor state. Everybody is haemorrhaging money and the haemorrhage is going to be too excessive for some clubs. It is a dire situation.
"We've already cut players' wages. They have not done that in football. All the staff have taken pay-cuts and you can't keep doing that. There has to be some sort of termination or some help."
Imploring the Government to ensure that "the cure isn't worse than the illness" with regard to Covid-19 protocols, Diamond expressed his hope that decision-makers consider the intangible impact of both Premiership and grass-roots clubs, especially in northern England, on their surrounding communities.
"We've done some research and something like 65 percent of England internationals have come from the North," he said. "There is only us and Newcastle [Falcons] in the North.
"Over the past five years, Sale alone has created 200 jobs. We get in front of 10 or 15,000 kids a year in deprived areas and all of that is in question at the minute.
"It isn't just about 16 home games and 16 away games in a season. It's the infrastructure that we provide."
- Daily Telegraph UK