Cameron set up a service where you can vollenteer to do just this. Its been around for years. And like any work experience training. You end up doing the unskilled stuff. Cos of course you will never gain any experience that requires qualification. At best you get to watch.
And even before Cameron charities offered and offer these services and many more.
This is literally just making a volentry thing mandatory. Nothing else at all.
You can do some volunteering without out degrees like with St Johns Ambulance who will give you the training to be a driver, event first aider, etc. I know a guy who volunteered as an ambulance driver who was an engineer by trade. Just as an example.