If working more than 48 hours a week is a genuinely free choice, then that's fine.
Senior managers' reward packages often reflect a need to work long hours (or at least to be available), and such staff are exempt from the provisions of the Working Time Directive (WTD). However, there is evidence that some employers include an obligation to be prepared to work more than 48 hours in contracts of employment - especially for more junior staff. There is no real choice in such situations.
Moreover, I would question whether working long hours actually enhances productivity. Perhaps working shorter, but smarter hours, would actually increase productivity.
I wonder if there is a correlation between our long working-hours culture and our lowly position on the World Competitiveness Scoreboard? (Personnel Today, 17 May)
HR strategy planning, Ministry of Defence