The analysis of the pay and jobs of women over the age of 50 shows that despite a dramatic rise in the number of women working past 50, low pay and pensioner poverty remain major concerns for them as they approach retirement.

A woman in her 50s working full-time currently earns £11.99 per hour - 18 per cent less hour than a man of a similar age (£14.69). This compares to a 10 per cent gender pay gap across the workforce as a whole. Women in their 50s also earn less than women in their 30s (£14.17) and 40s (£12.93).

But the TUC analysis shows that full-time earnings only tell half the story, with half all women over 50 employed in part-time work. The average hourly part-time wage for a woman in her 50s is just £8.53 - a third less than the average full-time wage across the UK workforce (£12.76). The majority of women over 50 in part-time work earn less than £10,000 a year.

The TUC analysis shows that older women have seen the fastest jobs growth in the last two decades. In 1992, the majority of women over 50 were not active in the labour market. Today, just 37 per cent of females over 50 are economically inactive, while three in five are in work.

But while rising employment rates for older women is good news, the TUC is concerned that a lack of good quality, part-time work means that many working women are still struggling to save enough for their retirement, despite working for longer than ever.

The analysis is the first in a series of reports for Age Immaterial, a TUC project looking at issues facing women aged over 50 in work, including pay, caring responsibilities, age and sex discrimination, and health issues.

TUC General Secretary Frances O'Grady said: 'The rising number of women over 50 in work has been the great success story of the last two decades.

'But while more women are working for longer, low pay remains a big problem, particularly for the millions who have been badly let down by the pension system and who are approaching retirement with little or no savings.

'Women over 50 earn nearly a fifth less than men of the same age and the pay divide for the 1.6m older women with part-time jobs is even starker.

'Part-time work is the only option available for many older women who also have to look after loved ones, either their grandchildren or their own parents, or who may no longer be able to work long hours. Most of these women earn less than £10,000 a year, barely enough to live on, let alone save for their retirement.

'As the workforce ages, it's essential that people are able to work part-time hours without having to give up decent pay. Most of us will have caring responsibilities at some point in our lives and it's not right that looking after loved ones still has such as a damaging affect on women's pay and career prospects.'