Every 71 seconds is incredible. I suspect in 10 years, half a million bicycles will be stolen in central London alone.
I think part of the problem is the fact that many people like to park bicyles on bike racks with inexpensive locks. If you're going to use a bike rack, the locks should weight nearly 25 lbs or more! The Kryptonite New York 3000 or Chain is the only lock I would use if locking the bike outside for significant amount of time.
You would think Brompton should use this as a marketing ploy since folders are rarely locked on bike racks. If you see stolen Bromptons for sale inexpensively, it's usually those that were locked outside a train station or bike rack.