Scotland's experience is relevant to the row raging south of the border about financial incentives for dementia diagnosis.

English GPs are to be paid £55 for every patient they identify with dementia, in a bid to tackle woeful levels of under-diagnosis.

But the scheme has been greeted with horror by many and described as an "ethical travesty" by Dr Martin Brunet, who wrote in medical magazine Pulse advising GPs to boycott "this odious scheme".

University of East Anglia medical ethics expert Dr Anna Smajdor said patients will wonder: "Are [doctors] listening to our problems, or mentally calculating how much money they can make from us?"

Timothy James of Birmingham City University, also has his doubts. "Surely doctors should diagnose illness to benefit their patients, not themselves?" he asks. But he adds: "Experience shows these financial incentives are very effective in changing GPs' practice."

Financial incentives were not necessary here when the Scottish Government increased diagnosis by 30 per cent over three years. Rates are now significantly higher than in England, which has the lowest level of any UK country.

But no country can be complacent because large numbers of those with symptoms are still being missed, according to Professor June Andrews, the international dementia expert at Stirling University. She has limited patience for the objections from GPs in England. These have included complaints that "false positives" might result as doctors identify cases mistakenly - lured by the extra £55 on offer.

Professor Andrews' argument is that overdiagnosis is so far from being the problem as to render such objections bizarre. England has a 20 per cent diagnosis rate, based on Europe-wide estimates of prevalence, she says.

The other argument is there is too little to offer those who are diagnose. But Professor Andrews argues those with an early diagnosis can take simple measures, like changing exercise regimes, increasing light levels in their home, or using self-help websites.

Meanwhile, any patient diagnosed with cancer but told there was no treatment or hospice available would still want to be told they were ill. And they and their relatives might well then demand better services. Why should dementia be different?

Services still need to be better, Professor Andrews says. But the ethics of payment incentives are a side issue, for dementia sufferers, and their families, she says. "We should go out and find them. Then go out and help them."