Andy Henderson and his partner, who live about 500-metres away from the Grampian Food factory in Eye, have expressed their frustration with the smell.

They say the smell prevents them and their children from enjoying their home and has got worse during the last six months.

"It's a nightmare. It is really disgusting – it stinks," said Mr Henderson.

"It has always smelled and my argument is that this is just not on in a residential area.

"We cannot even have the windows open," he said, adding he is starting a petition to quell the smell.

Grampian Foods spokesman Alistair Cox said: "The business has invested more than £100,000 addressing the odours at the site and continues to take measures to reduce them.

"Some odour abating equipment has been installed and this is ongoing."

Rita Penman, a spokesman for the Environment Agency, which regulates Grampian Foods Group, said the company has got planning permission to install an odour scrubbing unit. She also confirmed the business had invested in new buildings to contain the smell.

But Mr Henderson, who has lived in Eye for the past two years, said this issue has been a long-term one.

He said: "It has smelled for years and nothing changes. If they have equipment, then it is not working."

He added he and his partner , who wishes to remain anonymous, are in the process of moving their Eye-based boutique to Southwold, mostly as a result of the smell.

"People used to come into the shop and say that it stinks," he said.

Grampian Foods Eye was in discussions with the Environment Agency yesterday to discuss the issue but, as yet, no timescale has been agreed to install further equipment to eradicate the smell.