Scientists claim to have discovered a way to stop the build-up of a toxic protein in the brain that is considered to be a tell-tale sign of Alzheimer's.

Amyloid β protein has repeatedly been found to clog the brains of patients with the memory-robbing disorder, poisoning and killing crucial cells.

Researchers removed immune cells called microglia from the brains of mice with signs of Alzheimer's – studies have shown the cells 'turn on' genes for the disease.

Once the microglia were removed, the mice did not develop the hallmark amyloid β plaques. The team described the results of their study as 'striking'.

The researchers at the University of California, Irvine, hope their study will lead to new treatments that 'affect microglia in targeted ways'.

Dementia affects 850,000 people in the UK, of which 62 per cent have Alzheimer's, the most common form of the disease, according to the Alzheimer's Society.