The Brompton patent expired long ago. Flamingo or anyone else can copy Andrew Ritchie's design so long as they don't infringe the Brommie elements protected by copyright. Thus, Flamingo's bikes now have a visually different maintube (protectable by copyright), even though the function is the same (to protect function, one needs a a patent). The purpose of patents is tech transfer ... after patent expiry. I worked on a Brommie vs. Flammie case in the Low Countries. Brommie's use of copyright was like the choreography in Kill Bill 1 and 2.