That would be how much someone who switched to part-time at age 35 would lose out.

The figures have been calculated by long-term savings and pension group Standard Life, part of the Phoenix Group.

In its example, someone that began working full-time with a salary of £25,000 per year and paid the standard monthly auto-enrolment contributions (3% employee, 5% employer) from age of 22, would amass a total retirement fund of £434,000 at the age of 66. That is assuming 3% salary growth per year, and 5% a year investment growth.

However, if they were to switch to part-time (three days a week) from the age of 35, it would result in a total pot of £315,000 at the age of 66 – £119,000 less than if they remained working full-time.

Even switching to part time for a shorter period of 10 years comes with a sizeable pension penalty, the company warned.

Between age 35 and 45 those working full time will accumulate £44,400, while those working three or four days would accumulate £26,600 and £35,500 respectively over the 10-year period – a difference of almost £18,000 between full-time work and three days a week.

Neil Hugh, head of workplace proposition at Standard Life, said that women were more than three times as likely as men to work part-time and it will often be women that have to think more carefully about whether they are on track for the retirement they want.

He said: “At the spring Budget the Chancellor announced that from September 2025 all working parents in England of children aged from nine months will be able to access 30 hours free childcare a week, which should help those who want to stay in full-time work do so.

“However having children is just one of many reasons for the gender disparity – others include women taking on more caring responsibilities for adults and cultural norms in some parts of society.”