An 85-year-old man has been arrested on suspicion of attempted murder after he and his wife were taken to hospital suffering the effects of inhaling a "noxious substance."

The husband and his 86-year-old wife were taken to the Royal Cornwall Hospital at Treliske on Wednesday morning.

A carer calling at the house in the remote hamlet of Catchall, near Newlyn, raised the alarm just before 8am.

It is understood the elderly woman suffers from dementia and her husband is suspected of attempting to take both their lives.

One neighbour, who did not wish to be named, said: "I don't know them well as they live quietly.

"I've been told the lady has dementia and they are visited by carers to help them cope.

"This seems to be a terribly sad thing and I'm sure the family do not want any interference."

The exact nature of what police have described as a "noxious substance" has not been confirmed but officers suspect it to be carbon monoxide.

A police spokesman said: "An 85-year-old man was arrested on Thursday, September 2, on suspicion of attempted murder. He was later released on police bail until December 12 pending further investigations."

Speaking from the scene on Wednesday, Det Insp Tony Batchford said: "This morning two elderly people were taken to hospital with suspected carbon monoxide poisoning.

"A carer entered the house at about 8am and found this couple.

"The fire and ambulance crews were called."

A spokesman for South Western Ambulance Service said: "At 7.37am on September 1 two ambulances were sent to the address.

"This was treated as an emergency situation because the two patients were quite elderly.

"They were taken to Treliske."

The woman remains in a stable condition in hospital. Her husband is believed to be with family members.