"He's not an engineer, he's a trainee manager with no technical qualifications," Sugg said.
"We were there to inspect the fountain and to install a drainage pipe to help water dissipate. Otherwise the water, especially in a wet year like this one, will stay still and cause trouble."
As for Monroe's claims, Sugg told ABC News that CCE's ex-employee "was on sick leave in December, for practically the whole month, after which he resigned."
"The day after his resignation, we suddenly saw his statement to the press," Sugg said.
But Monroe told ABC News that he has over 14 years experience as a drainage engineer, having worked for companies such as Robert McCalpine, one of the UK's leading construction companies specializing in civil engineering.
He says he was called in November to help when the fountain needed maintenance.
"At that time Mike (Sugg) was in Disneyland," Monroe told ABC News. "It was his idea to install a new foot and land drainage pipe to control the leaks but the pipe I was asked to install was insufficient."
The native Scotsman alleges there was a severe leak between the base of the fountain and the concrete slab it sits on.
"There was water pouring out from the joint – I would have had to have gotten underneath to fix it properly. But Mike told me to put the pipe in anyway, cover it up and keep the press away," Monroe said.
"And," he added, "if anybody asked, to say it was just a routine maintenance job."
As for CCE's claims that he left after taking one month of sick leave, Monroe retorted, "I left the company because I like to work in an honest professional manner. I don't believe anything should be hidden."
Monroe also confessed he was saddened to see the princess's memory scarred by what he calls "an unfitting tribute."
Only a thorough examination of the fountain could prove if Monroe's allegations are true.
But it's unlikely that the latest storm over the princess's fountain will die down, unless a new controversy comes along to take its place.
Now that heart surgeon Hasnat Khan is poised -- possibly in a matter of weeks -- to discuss his love affair with the princess for the first time when he takes the stand at the inquest into her death, concerns about the state of her memorial will probably be consigned to the inside pages of Britain's tabloids.
Fabiola Antezana contributed to the reporting of this story.