Tens of thousands of women over 50 are being left on the jobless scrapheap years before retirement because they are forced to care for elderly, sick or disabled people in their family.

In total, up to 600,000 late middle-aged women are unemployed and looking for work, costing the economy up to £20billion a year.

The startling new figure is released today as Dr Ros Altmann, the Government’s Business Champion for Older Workers, ahead of a major report next week setting out the steps needed to end the crisis of older people shunted out of work years before retirement.

It will highlight caring responsibilities as one of the major barriers preventing women in their 50s and 60s from staying in work.

Almost one in four women aged between 50-64 care for elderly, sick or disabled people – with some 153,000 women approaching retirement claiming Carers Allowance – compared to just 87,000 men.

The caring responsibilities are hitting women’s job prospects – with the employment rate among 50-64 year old women just 63.7 per cent compared to 74.5 per cent for men.

Speaking ahead of the launch of her report on Wednesday Dr Altmann told MailOnline: ‘We need to harness the potential of older female workers, and provide support for those who would like to work, but feel unable to do so.

‘Caring responsibilities can often take women out of the workforce – but if businesses could accommodate more flexible working, often just for a short period, many more women could keep in touch with work and the employer would retain their invaluable experience.’

A YouGov poll recently commissioned by the Department for Work and Pensions shows that older women would prefer part-time work as they approach retirement.

Some 43 per cent of women who are not retired said the best way to retire would be to cut down to part-time or flexible hours before stopping work altogether.

Pensions Minister Steve Webb said: ‘This analysis shows how supporting older workers to stay in jobs is an essential economic priority for the UK.

‘The Coalition Government has taken bold action and is turning the tide, but there is more to do – particularly to help older women combine work with caring responsibilities.

‘Business in Britain needs to realise the potential of all older workers and take action on this. In the past we were too quick to write people off in this country once they reached a certain age, but the world has changed.’