Qualification for the discount can start either from when a GP certifies a patient’s diagnosis (severe mental impairment) or from when they receive a state benefit, usually attendance allowance, when they have reached state pension age. This involves a process of filling in a 31-page form and a wait of six months or more. 

At present it is up to councils to decide when to offer relief. Many families are unaware of it anyway so never apply.

Derek, 70, tried and failed to get Hambleton District Council, his authority in Northallerton, north Yorkshire, to backdate the discount to when Margaret was diagnosed three years ago. 

++ If you’ve been affected by this issue or feel you’ve been a victim of injustice, please contact consumer and small business champion Maisha Frost on maisha.frost@express.co.uk ++

That spurred him to probe deeper. His research, including Freedom of Information requests, found that “because the unclear way the law is worded there is inconsistent interpretation,” he says.

“This denies families relief at a crucial time, 255 UK councils start the discount when state benefit is received, while 127 believe it begins with GP certification.”

Ever deeper frustration with the inequalities led to him mounting a High Court challenge, representing himself and facing down a battery of legal top guns. 

“I was cut short by the judge several times, but I wasn’t crushed, ordinary people should be heard,” he told Crusader.

He lost the case, although was saved from paying ruinous costs.

He is now channelling his unstinting efforts into rectifying the anomalies through a petition to get the matter considered by Parliament. 

There are more than one million people in the UK with dementia, 950,000 of those over 65.  

Dementia Action Week, which gives the public the chance to improve the lives of those affected, runs from Monday May 17 to Sunday May 23. 

“Care for us is round the clock, love is why we do it, we want to stay together in our homes for as long as we can,” declares Derek. “This discount discriminates, it’s wrong.”

For Derek’s petition, visit: https://petition.parliament.uk/petitions/572993

Alzheimer’s Society head of policy Gavin Terry roundly condemns the current discount situation.

“It’s absolutely criminal that people with dementia aren’t getting the financial help they are entitled to,” he says.

“As it stands, people with severe dementia are eligible for discounts or even exemptions on their council tax, but we know from talking to people affected by dementia that they often aren’t aware of these crucial entitlements.

“What is even more confusing, is that some local authorities are not backdating the discount to the point at which a person is certified as having severe dementia, while others are – this is unfair, and this is what Derek’s campaign is seeking to change.

“Alzheimer’s Society echoes Derek’s call for this discount to be backdated and for all local authorities to ensure there is a clear and consistent process going forwards. 

“At present, a person’s entitlement is dependent on their postcode, and that cannot be right.” 

Alzheimer’s Society provides a support line for carers: 0333 150 3456.