Bikes from the Police bike pound were refurbished and painted green by offenders doing community service. The police officer in charge of the pound said that in all his years in Cambridge he'd seen some pretty stupid things but this...
Bike stands were erected at a number of sites around the City, along with a big "Green Bike Scheme" notice explaining that anyone could use the bikes provided they were left at another such site and not locked.
On day 1 of the scheme a number of bikes (50?) were distributed between these sites. Within about a day all had gone.
After a couple of months another batch of bikes was released, which went just as quickly.
[The day after the scheme was formally abandoned, in April 1994, I saw my first Green Bike. I've heard similar reports from many others.]