Is this the age women’s careers grind to a halt?

Promotion prospects for women grind to a halt at around age 45, according to new research for the British government – a decade sooner than for men.

In a report looking at older people in the workforce, author Ros Altmann, who is the U.K. government's "business champion for older workers," found that talent progression for older women was "limited."

Melinda Gates: Tackling gender wage gap
Melinda Gates: Tackling gender wage gap

"Older women face particular barriers in the workplace,"Altmann wrote in the report issued this week.

"For example, I have been told that talent progression for women stops around age 45. After that, the attitudes in the workplace usually change (for men it is said to be around age 55)."

It comes just days after philanthropist Melinda Gates and former U.S. Secretary of State Hillary Rodham Clinton unveiled new analysis of global gender inequality.

Gates, who is co-chair of The Bill & Melinda Gates Foundation, told CNBC's "Squawk Box" that women around the world need to be encouraged to participate in the workforce at the same rate as men.

"The (gender) gaps are particularly in the area of employment. That is, having labor force participation equal to men. We're not even close yet," Gates said.

Maximilian Stock | Getty Images

The analysis by The Bill & Melinda Gates Foundation and The Clinton Foundation found that although progress for women had been made in some areas, "critical barriers" remained.

Read MoreThe No. 1 reason women are not getting promoted

"Women's participation in the labor force has stagnated for two decades—and they still earn less than men," the report said, and highlighted that women remained under-represented in leadership positions across the world.

In the U.K., Altmann found that older women face a number of hurdles when it comes to work, such as the frequent need to combine work and caring for ageing parents. Many are also disadvantaged in state and private pensions, she argued, as a result of lower wages than men, and of having taken time out to have children earlier in their careers.

But the report found that older women could make a major contribution to the economy. If 600,000 more older women worked part-time, some £9 billion could be added to U.K. gross domestic product (GDP) each year, the report found, and this amount rises to £20 billion if these women worked full-time.

"The potential economic gain from having more older women in the workplace is significant," Altmann added.

- By CNBC's Katrina Bishop