The Mk1 Raleigh Chopper started production in 1969 and lasted until Dec 1972, a safety construction problem was the main reason for replacing the MK1 the rear drop outs tubing kept breaking, despite various attempts to change the design. The adjustable handlebars caused a bit of concern too as they had a tendency to "adjust" on their own, quickly dumping the rider on the floor and the long seat lending itself to "two ups" and this leading to the bike wheeling, probably the reason for some of the rear frames that broke. So all in all the poor old Mk1 was sort lived.