Brompton have collaborated with 'Quad Lock' to bring out there own universal adapter so that you can have your phone mounted securely and safely, slap bang in the middle of your handlebars.
Positioned in the centre of the handlebars over the stem and held in place but a double bracket, it really is a clever little addition.
Lots of people use their phones for navigation and there are all sorts of ways you can try and lash your phone to your Brompton but this is definitely the best I have seen.
There are two versions. for £35 you can just buy the mount for the handlebars - as lots of people might already have the comparable case for the their phones. For £45 you can buy the pack that has the mount and universal adapter that you stick to your existing phone case. (As seen in the photo below).
It really is rather clever and even with the mount installed, there is still a little real estate on the handlebars for a few other items as long as they aren't too big.
I suspect these will quite literally fly off the shelves.