New research has revealed how UK mums are earning less throughout their careers, at least part of which can be put down to the bias of part time work for their demographic.

The UK gender pay gap has been pretty stubborn for many years and is still running at around 20 per cent. The new research is from the Institute for Fiscal Studies (IFS), and was carried out at the request of the Joseph Rowntree Foundation, an independent organisation which works to inspire social change through research, policy and practice.

The research shows that part time workers often don’t receive the annual pay rises which their full time counterparts do, with mothers in particular singled out as missing out. The study also highlights that part time staff tend to suffer from a lack of promotion in the workplace too.

Women make up a huge proportion of the part time workforce in the UK and female graduates in particular seem to be suffering when it comes to hourly pay growth. Overall, women graduates earn over 20 per cent less per hour than male graduates.

With mothers working part time more often than fathers, the report revealed that two decades after having their first child, the woman would tend to be earning almost a third less than the man.

Commenting on the report, Head of Analysis at the Joseph Rowntree Foundation, Helen Barnard, said: “It’s just not right that we treat part-time workers as if they are less valuable than full timers. Millions of women and men want, and need, to work but also have responsibilities to children, partners, or parents. Many more have health conditions that mean they can work but can’t always manage full-time hours.”

“We can redesign the jobs market so it works for everyone. Employers can increase the number and quality of jobs open to part-time workers and hire flexibly rather than only allowing existing employees to negotiate part-time hours,” added Ms Barnard.

Robert Joyce, an author of the report and an associate director at the Institute for Fiscal Studies (IFS), commented on the changing landscape in the work market, saying: “Traditionally it has been lower-educated women whose wages were especially low relative to similarly educated men. It is now the highest-educated women whose wages are the furthest behind their male counterparts. This is particularly related to the fact that they lose out so badly from working part time.”

Another IFS associate director and contributor to the report, Monica Costa Dias, said: “There are many likely reasons for persistent gaps in the wages of men and women, which research is still investigating, but the fact that working part time has a long-term depressing effect is an important contributing factor.”

“It is remarkable that periods spent in part-time work lead to virtually no wage progression. It should be a priority for governments and others to understand the reasons for this. Addressing it would have the potential to narrow the gender wage gap significantly,” added Ms Costa Dias.

Why not read our complete guide to the best part time jobs for mums and put your spare time to profitable use?