What do these people have in common: Anna Ford, Selina Scott, Nick Ross? For one they are all former BBC presenters. For another they are all older people. Most importantly none is on television any more, allegedly because of their age.

To their ranks you can add former Countryfile host Miriam O'Reilly, below. She is in the midst of an employment tribunal with the BBC, claiming she was a victim of age and sex discrimination after being rejected for the new prime-time version of the show.

Whatever the outcome of the case it casts light on a broader issue: ageism within TV and society at large. Regardless of the verdict those at Anchor, the country's largest not-for-profit provider of care and accommodation for older people, believe that the case must spark a debate about ageism and its effects.

Anchor recently commissioned research into the number of older faces on the main terrestrial channels and found a shocking absence of people in the prime of their lives at prime-time.

BBC1 fared worse than ITV1. Only 20 per cent of presenters and actors on the BBC's flagship channel were over 50, compared with 27 per cent on its main commercial rival. Even ITV fell short of reflecting the face of the general population in which 34 per cent are in their 50s or older.

It is an incredible discrepancy. It seems scandalous that the over-50s are not represented more fairly on TV, particularly when they are the fastest growing demographic in this country.

David Cameron, during the election campaign in April, was right to suggest that our media has an obsession with youth, sometimes to the exclusion of other sections of the population.

This fixation means that in many aspects of society there is simply no recognition of the skills and abilities older people have.

With the media glare so focused in one direction those left in the shadows are being increasingly isolated.

This is manifesting itself in different ways. One is a strong sense of political marginalisation among older people. According to our research 63 per cent of over-65s feel overlooked by politicians and only a quarter agree that their MP understands the issues affecting them. Given the ages of David Cameron (44), Nick Clegg (43) and Ed Miliband (40), this is perhaps not surprising.

Another way in which marginalisation manifests itself is in the sense of fear this lack of representation brings.

Further Anchor research found 45 per cent of over-65s fear government cuts have increased the likelihood of them having to sell their home to pay for care.

It seems the political agenda, dictated more and more by the media and its fixation with youth, is creating a system that is neither representative of nor appealing to a huge proportion of society. This is particularly disappointing given that today's older people are leading longer, more active and independent lives.

We should remember that many grew up in the era of The Beatles, Stones and Lady Chatterley. Not only are they more active than their pre decessors they also bring invaluable skills, experi ences and attitudes that other parts of the community do not have.

Redressing this imbalance and the institutionalised fixation with youth that has caused it is far from straightforward but can be done. TV executives have a key role to play. They are in a unique position to reach into the living room of households across the country and must use this responsibility wisely. They set the tone for what is seen as mainstream and "normal".

Rather than condemning older presenters and actors to the scrapheap it is time they embraced the wealth of talent and experience they offer.

At the same time, Anchor believes that the Conservatives "Big Society" initiative may provide a springboard for change. One element of the Government's vision for adult social care was to ensure older people have an active role in building Big Society communities. This is a small step in the right direction.

It will take many such other steps but through a united effort from politicians and the media we can ensure that older people are not consigned to the shadows.

Instead they should be in the spotlight, living the prime of their lives in the glare of prime-time.