Brompton's a company admirably sticking to their roots by continuing to design/manufacture in their birthplace of West London. While that can't be cheap, the company points out that "Moving production offshore in search of lower labour costs, business rates and taxes would certainly bring some obvious benefits, but these would be outweighed by the consequences of losing control over quality and, ultimately, losing the confidence of the consumer." Hear hear.
They've put together an inside-the-factory video, so you can see where the magic happens.
The 22,000 sq-ft Brompton Bicycle factory is on an industrial site nestled between railway lines and a motorway. The brazing, assembly and engineering areas share one building with the office space, and most of us, from bike builders to the managing director, use a Brompton ourselves, so we have a good feel for how the product should be. We give great attention to training on the shop floor and every operator is always made aware of how every job he or she does contributes to the finished product.
The Brompton consists of some 1,200 parts, over three-quarters of which are unique to our bicycles (exceptions include the chain and various screws, washers and other sundry fixtures). As most parts have had to be designed in-house to meet our particular needs, we have also had to design and build the machines, tools and fixtures needed to manufacture them, including over 500 purpose-made press tools, moulds, braze jigs and assembly fixtures. We are continually refining our manufacturing methods, raising productivity, and every year sees a large investment in new machinery and equipment.
There's no narrative explaining the particular operations depicted, so you'll have to put your production methods caps on and do some manufacturing math. (You'll also catch fleeting glimpses of some of those custom jigs they mentioned, cool stuff.)