They found that in 13 of the 15 countries, people with lower educational qualifications were more likely to leave the labour market by being let go, or made redundant, than more highly educated people.

This is because increased education provides individuals with opportunities to exit the labour market voluntarily, as doing so is typically associated with more attractive, more stable, higher-income, and healthier working conditions.

"The demographic change represents one of the greatest financial challenges for European pension systems and, to counteract this, political measures - such as raising the statutory retirement age or curtailing early-retirement options - have been adopted in almost all European countries.

"However, depending on their levels of education, these measures affect older workers differently, which, in turn, runs the risk of exacerbating social inequalities. As lower-income workers are more likely to leave the labour market involuntarily, this could widen the pension gaps after the end of working lives - which is known as the social gradient," says Dr. Jana Mäcken.

This social gradient was highest in the Czech Republic, Germany, and Portugal and lowest in the Netherlands and Denmark.

The research reveals that for lower educated workers, it is more difficult to reach the new political goal of extending workers lives.

For this reason, the researchers suggest policies that provide training opportunities specifically for less educated workers to help reduce educational inequalities in the labour market.

Furthermore, stricter employment protection legislation would lead to a lower social gradient in involuntary labour market exit.

The study was published in the Journal of Social Policy.