Red and Yellow Care Ltd wants to build 400 two and three-storey privately-owned homes for dementia sufferers at the Medi Parc site, in Hill End Road.

Tina Wane, chairman of the campaign group Save the Medi Parc, estimates this will increase the population of the village by 10 per cent – an increase she is not sure the village can handle.

Mrs Wane shared concerns surrounding the allocation of properties, the procedure when a dementia patient dies, and the effect the increase in population will have on the infrastructure of Harefield, in a newsletter distributed to villagers.

“We very much appreciate residents’ concerns,” said Dr Bahbak Miremadi, director of Red and Yellow.

“We are looking at many different ways we can integrate with the Harefield community, including healthcare, education and shared public spaces and facilities.”

He explained how the homes would be allocated.

“The average age of our residents will be between 75 and 85,” he said.

“The prospective resident will arrive with an established diagnosis, given to them by a health professional such as a GP, or via a memory clinic.

“Red and Yellow will allocate a named dementia nurse, who will review their diagnosis as part of a needs assessment to help them choose the right accommodation and care package.

“Part of the unique offering of this community is that it will allow loved ones to remain together when one has dementia.

“It is currently the case that many are sadly split up. We have decided that it would be inappropriate to ask the partner of a person with dementia to leave the community once they have passed away.”

Remaining spouses would be welcome to live in the property for as long as they wish, but their leases would not allow them to hand the property on to another member of the family.

“Red and Yellow will help them resell the property on to another person with dementia,” he added.

“This will be a specialist healthcare community whose aim is to raise the quality of life for people with dementia and their families.”

The Medi Parc sits in the green belt. In 2011, villagers tried but failed to get the land designated as a village green to prevent its development.

A public consultation date is yet to be set.

In January, Red and Yellow held a public question and answer session.