https://phys.org/news/2019-01-part-time-mothers-flexible.html

They did this by using data from the Understanding Society surveys carried out between 2010-2015 to examine three types of flexible working that people use and how it impacted their workloads:

For the first two types of flexible working, there was little evidence of an increase in unpaid overtime hours, but they did not detect a decrease in overtime hours for this group either.