In a speech to a conference hosted by Help the Aged and Age Concern which have merged, Mr Johnson said old age no longer begins at 65 with many people remaining active well beyond that.

People in their 60s and 70s are more likely to be riding a mountain bike than playing dominoes in their local day centre, he said.

He warned the conference in London, that because of increasing life expectancy and the growing numbers of elderly people would pose serious problems for society and the economy meaning automatic retirement at 65 would have to be 'consigned to history'.

While the facts about ageing have changed 'the fiction remains' he said, meaning that in work and in healthcare, older people are treated differently because of their age.

In the NHS he said dementia is often dismissed as an inevitable consequence of growing older and many old people find it hard to get help for mental health problems.

Mr Johnson announced that Sir Ian Carruthers, chief executive of South West strategic health authority and Jan Ormondroyd, chief executive of Bristol City Council will lead an in-depth review of how the NHS and local authorities can effectively tackle discrimination against older people and will report back in October.

On social care, Mr Johnson said while there had been improvements, he admitted there was a 'simple and inescapable fact that in general, the current social care system is inconsistent, incoherent and no longer sustainable'.

The number of people with dementia, currently at 700,000 in the UK, will double in 30 years. If the current 'inadequate' system were to continue, he said, there would be a shortfall of £6bn by 2020.

Mr Johnson said in some parts of the country older people are supported so they can stay in their home while in others there is no choice but to be 'shuffled off into a care home'. He added that many families spend days or weeks trying to navigate the system 'making endless phone calls'.

Reforms had to offer real choice while ensuring basic care standards are the same 'whatever their postcode', he said.