Baking

I'm going to be making cakes tonight to take into work tomorrow. Whatever I make should be (a)easy to make, (b)capable of surviving a walk and a train journey, and (c)either dairy-free or with only a small amount of dairy produce (I can do milk, but butter will be margarine and I can't do cream). Has anyone got any suggestions? I'd quite like to demonstrate something fairly British for the members of my team who are from other countries, but that's not absolutely necessary.

I've got as far as thinking of flapjacks or fairy cakes, but ideally I'd like something different.