I year in industry is good, but the engineering jobs market isn't so competitive that you simply must have that years' experience before graduation to have any chance of securing a job. As History98 points out, a year in industry can be a lost income of circa £10,000. Obviously, you can't bank on getting a job after university, but if you're a good engineering student and manage to get some form of work experience alongside your studies, e.g. a summer placement, it's a good bet that you'll get one.
I'm not trying to dissuade anyone with the above, but it's definitely something to consider.