I would have to guess it is the pay and that none of the jobs (very limited) are really "civil engineering" as we might expect them to be based on this site.

What can I do with a civil engineering degree Prospects.ac.uk
https://www.prospects.ac.uk/careers-advice/what-can-i-do-with-my-degree/civil-engineering

>Employers hiring civil engineering graduates now
>Mechanical Engineer Apprentice - Cumbria
>
> Babcock
> Cumbria
> £17,001-£19,500
>
>Graduate R&D Design Engineer
>
> Pilkington Technology Management Limited
> Ormskirk
> £24,501-£27,000
>
>Nuclear Engineer Graduate Programme
>
> BAE Systems
> Barrow-in-Furness
> £32,001-£34,500

I am pretty sure that at those pay levels you either need several roommates or need to live at home.