More than a third of dementia patients are denied the best care, a charity said yesterday.
They should all be given an individual treatment plan when they are diagnosed.
But figures compiled by Age UK show that only 62 per cent of patients receive one.
This means tens of thousands miss out on counselling sessions, home visits from specialist nurses and activities such as dance and art.
Age UK said care provision varied widely across the country. In Norfolk patients in the later stages of dementia are given 'admiral' nurses trained to deal with their needs.
More than a third of dementia patients are denied the best care, a charity said.
Camden in north London offers weekly counselling sessions to help sufferers come to terms with their illness – but patients elsewhere say they are all but abandoned.
'Our analysis suggests many people with dementia are losing out on the NHS follow-up support they need and are supposed always to be offered, once they have received their diagnosis,' said Caroline Abrahams of Age UK. 'They and their loved ones are missing precious opportunities to get help with living as well as possible with the disease.
'The absence of a care plan also means people with dementia are not being signposted to services that could improve their physical and mental health, and sense of wellbeing.
'There aren't enough good local services yet, but some great initiatives do exist, as we show in our report – so it's a terrible shame if people aren't being helped to access them.'
Dementia patients should all be given an individual treatment plan when they're diagnosed but figures compiled by Age UK show that only 62 per cent of patients receive one.
The charity analysed data from 7,185 GP practices and found that 458,461 adults had a recorded diagnosis of dementia in November 2017. However, only 282,573 had an up-to-date care plan.
The plans should be updated at least once a year as the illness progresses, according to guidelines from NHS England – the body responsible for running the Health Service. Dominic Carter of the Alzheimer's Society said: 'People with dementia often tell us that, after being given a diagnosis, they got little or no state support.
'We have more understanding than ever about dementia, but chronic underfunding and lack of integration across health and social care means practical support is not so freely available.'
An NHS England spokesman said: 'The NHS has worked hard to dramatically increase the number of people receiving a formal dementia diagnosis so they can access the right care and support.
'A care plan is only part of high-quality dementia support, which is why we have introduced new measures to help local NHS groups and GPs plan for ongoing care and will continue to help deliver further improvements.'
Around 850,000 people are believed to have dementia in the UK. The Age UK figure is lower because not all patients are given a formal diagnosis, and the charity's count covers only England.