Brompton’s folding bike patent expired a long time ago (in 1999), though Brompton have been in court trying to prevent other makers from using their design claiming that their bicycle design is “copyrighted.” Their argument is that their design drawings were copyrighted when the bicycle was designed, and anyone using written plans similar to those made by Brompton are infringing on Brompton’s copyright.

It’s not likely that Brompton will prevail in the long run, and makers in Asia have been producing their own versions for a long time. I can find many Brompton-type bikes here in Japan which sell for much less than the real thing, and many of them are technologically superior. You can get a Brompton-type bike with disk brakes, conventional drivelines using off-the-shelf parts, etc. I dislike the idea of using a copyright in place of a patent to extend ownership of a design almost indefinitely; patents are not permanent as it could give corporations virtual monopolies on a wide range of products.