Most of these employers will look at A level results as much as degree results, in my experience.
To further this, having relevant work experience or any for that matter. As part of my degree I took a placement year, so I did not have to fuss around in my final year trying to look for a job.
Anybody that studies Computer Science most definitely has a big interest in the subject to get through the Degree. I've seen some module work from a CS course and it looks painful. Top Degree to get though!
In most of my lectures I sat there thinking 'Dude, what is this guy going on about? All I want is to make a video game....'