Workers in offices at Aylesbury's Blue Leanie building say they have had enough of working in temperatures in excess of 35C due to a long-running problem with the air conditioning units.
The problem is understood to affect businesses on floors two, three and four at the building on Walton Street - approximately 300 people.
An employee at one of the affected businesses Identify Group told the Bucks Herald: "There has been a long-running problem with the air conditioning not working meaning it gets very hot in the building.
"We moved in in June 2018 and it has been an issue since then.
"It affects three companies across three floors - around 300 people in total.
"Whenever we approach the landlord he says it is 'being dealt with' but nothing has happened.
"We have recorded the temperature inside our office as being 35C at times.
"Once the temperature outside gets to around 17 or 18C it gets very hot in here and if the temperature outside is around 20C it becomes a real problem.
"People have become grouchy and miserable, it affects their productivity and ability to work and in some cases people have had to go home because they feel sick.
"We feel the building is not 'fit for purpose' and that the current situation could put potential tenants off.
"It is a lovely and iconic building to be in, but we pay a lot of money for the privilege, and we want better working conditions in hot weather than what we currently get.
"On a day like today (the outside temperature at the time of writing was around 10C) it is a lovely place to work and very comfortable - it is just the heat that is a problem."
It is understood that the first floor of the building does have functioning air conditioning and is not affected by this issue.
A spokesman for the Blue Leanie's owners London & Scottish Property Asset Management Limited said: "Since acquiring the building in March 2016, an extensive refurbishment was commissioned by LSPAM on behalf of its client Regional REIT.
"This included the refurbishment of the heating and cooling systems in 2017, all under the recommendations and guidance of a specialist consultant.
"We are in active dialogue with all stakeholders involved on this to ensure good relations with the tenant and a satisfactory outcome."