Ever wondered what happened to those trucks you used to run? Are they still on the road or have they been turned into Chinese-made washing machines?
If you are sad like me, and this sort of thing appeals, you'll probably spend hours on this DVLA website.
Just click on Vehicle Enquiry, enter the number plate details and then scroll through the list to find the vehicle's make.
Here's a couple of good examples:
This AEC Mercury had a surprisingly long life. It was purchased new by Mackintosh back in 1966, and incredibly was still taxed and on the road in 1990.

This Foden faired slightly worse. It was first registered in 1972 and was last taxed in the UK in 1984. Of course we don't know whether it was scrapped, exported, or is actually still in sitting in the corner of someone's yard.