Dementia is being missed by hospital doctors in four in ten cases, research shows.

The study by University College London found medical staff are routinely treating patients without realising that they had been diagnosed with dementia.

Researchers said the failure to properly record their illness meant vulnerable elderly people were being discharged from hospital with instructions to take crucial medication, without medics realising that they were likely to be suffering from memory problems.

They said too many pensioners were being admitted to hospital with physical health problems, without proper records being kept of other diagnoses like dementia which could affect them profoundly.

The research examined 138,455 hospital admissions from 21,387 people between 2008 and 2016, including 37,329 admissions of 8,246 people who had known dementia before general hospital admission.