The Scottish Government's failure to deliver on a promise of support for people who are diagnosed with dementia has been described as "shameful", "inexcusable" and "unacceptable" by opponents, after figures revealed only two in every five patients get the help that they should.

Five years ago ministers pledged that everyone diagnosed with dementia would receive a minimum of 12 months support as they come to terms with their illness.

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Each is supposed to get a named link worker who will work alongside them and their family for a year, to help put together a holistic, personalised care plan.

But new NHS Board performance data reveals that health boards are missing the target of providing this for all new patients by a wide margin.

61 per cent of the 17,496 people newly diagnosed with dementia in 2016/17 did not receive this post-diagnostic support (PDS).

Just over 8,000 were referred for the help but only fewer than 7,000 actually received a package of support.

While the best performing board, NHS Lanarkshire managed to deliver for 61.3 per cent of its patients, fewer than one in five in NHS Grampian and barely one in ten at NHS Orkney received it.

NHS Greater Glasgow and Clyde has improved the most in the last year, with 56.3 per cent of patients now receiving support compared with 45.5 per cent in 2016, whereas health boards covering Ayrshire and Arran, Borders, Fife, Lothian and Orkney are going backwards.

Jim Pearson, Director of Policy & Research from Alzheimer Scotland, said the charity was deeply disappointed that the "world-leading commitment" was not being achieved.

"We know from experience that this crucial support can make a real difference for people with dementia, their families and carers. It can also help avoid wasting vital resources through preventable and costly crisis care," he said.

"There has been progress, but it is slowing down. Alzheimer Scotland is deeply disappointed that five years after this national guarantee was made, fewer than half of those entitled to it are offered post diagnostic support. That is not good enough for people living with dementia, or for our health and social care systems which cannot afford to continue to be crisis-driven."

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Age Scotland branded the figures “inexcusable” and said the increasing numbers of people living with dementia in Scotland deserved better.

The charity's Chief Executive Brian Sloan said: “Not only have 61% of people newly diagnosed with dementia gone without the promised care, but less than half of the total were actually referred in the first place. This is clearly not good enough and is a staggering disservice to those living with dementia, their carers and family.

“On the face of it there is a wildly unacceptable postcode lottery which will give Scottish Government Ministers and NHS officials a further reason for embarrassment.

He said the demographic changes facing the country meant it was vital ministers came good on their promise to people with dementia.

“As the Scottish population ages at a significant rate, and those living with dementia predicted to increase by 50% over the next 20 years, they must do better and quickly. There are big questions to answer about why people haven’t been referred and why the 1,348 people who had, didn’t get the care they were promised.”

Scottish Conservative mental health spokeswoman Annie Wells said: “The target set is that every person with dementia should receive these support packages for at least a year after being diagnosed. Yet despite this SNP pledge, fewer than half are being referred. And of those who are, not even all of them are getting the support they need.

"Every year the number of people diagnosed with this cruel condition increases, and that should be matched by improvements in care and performance. Yet on the SNP’s watch, it continues to be completely unacceptable."

Scottish Labour Health spokesperson Monica Lennon said: “These figures are utterly shameful. Our health service has to adapt to the challenges of the future, and more and more people are being diagnosed with dementia each year.

“The SNP has been in charge for more than a decade. They must urgently ensure people get the support they need."

Liberal Democrat health spokesman Alex Cole-Hamilton said the target was being “missed by a huge margin” and added: “A coordinated package of support can make a big difference to individual patients and their family as they understand and adjust to a diagnosis.

“A plan helps people live well with dementia, ensuring they are accessing the right services and finding the best ways to manage their symptoms.”

Minister for Mental Health Clare Haughey said:

“Over the last decade dementia services have been modernised, supported by our world-leading work on post-diagnostic support, but we recognise that there is more to do to support local partnerships to extend access to this service. Life expectancy in Scotland is at a record high, and our growing and ageing population makes dementia more common.

“Many people are diagnosed into very old age with other chronic or terminal conditions and for some their dementia support – including in residential care – will be given in addition to existing care packages and not reflected in the post-diagnostic figures.

“We are currently testing the re-location of dementia post-diagnostic support in primary care and we have also recently commissioned new work to examine the delivery of the service for people with a high level of additional care and support needs.”