Spotted...

Spotted a Brompton undertaking a blue on one. Pulled up next to the brompton, put on my best charm, and mentioned that, althought the on-one rider was paying attention and seemed a very competant rider, many other riders might not have noticed him on the inside and it would be safer not to pass someone this way.

He actually thanked me for the advise. It made my day.

Oh, this gives me hope! I'd given up giving people advice about undertaking, after all the abuse I got.